Question: 2025年02月21日至2025年04月25日，浪潮信息股价跌破20日双指数移动平均线的次数是多少？（平滑系数 alpha 取 2 / (n + 1)；从前 5n 个数据开始计算；初始值用首个数据点）使用不复权价格，写出指标公式，搜集原始数据，计算得出答案，保留四位小数。注意列出原始数据和关键计算过程。
Formula: DEMA = 2 * EMA1 - EMA2；EMA1 = EMA_n(P)；EMA2 = EMA_n(EMA1)
Data:
date,close,high,low
2024-09-18,31.18,31.33,30.7
2024-09-19,31.64,31.98,30.93
2024-09-20,32.37,32.57,31.59
2024-09-23,32.21,32.79,32.02
2024-09-24,33.5,33.52,32.03
2024-09-25,33.3,34.37,33.27
2024-09-26,34.3,34.3,33.2
2024-09-27,37.73,37.73,34.68
2024-09-30,41.5,41.5,38.88
2024-10-08,45.65,45.65,42.2
2024-10-09,43.2,47.0,42.0
2024-10-10,41.27,43.99,40.56
2024-10-11,39.5,41.27,39.0
2024-10-14,40.45,40.59,38.8
2024-10-15,41.79,44.15,41.71
2024-10-16,40.91,41.66,40.58
2024-10-17,41.63,43.23,41.18
2024-10-18,43.4,44.77,41.31
2024-10-21,43.62,45.15,43.41
2024-10-22,43.29,43.95,42.8
2024-10-23,43.85,45.12,42.93
2024-10-24,43.02,43.57,42.51
2024-10-25,43.2,43.59,42.71
2024-10-28,43.58,43.9,42.97
2024-10-29,44.51,46.44,42.89
2024-10-30,44.83,45.5,43.77
2024-10-31,46.78,47.5,45.03
2024-11-01,43.7,48.42,43.51
2024-11-04,46.1,46.61,43.25
2024-11-05,47.45,48.38,45.4
2024-11-06,46.4,47.7,46.0
2024-11-07,47.01,47.18,45.25
2024-11-08,51.71,51.71,47.55
2024-11-11,54.72,56.88,52.8
2024-11-12,55.88,56.7,53.12
2024-11-13,57.01,59.5,54.78
2024-11-14,52.4,56.16,52.3
2024-11-15,49.21,53.4,49.19
2024-11-18,46.92,49.75,46.24
2024-11-19,48.9,49.84,46.12
2024-11-20,48.89,49.81,48.15
2024-11-21,49.26,50.05,48.5
2024-11-22,47.71,50.97,47.48
2024-11-25,46.45,47.87,44.9
2024-11-26,45.29,46.58,45.26
2024-11-27,46.62,46.63,44.56
2024-11-28,47.21,48.99,46.32
2024-11-29,47.8,48.6,46.31
2024-12-02,48.03,48.37,47.51
2024-12-03,46.5,48.15,45.9
2024-12-04,46.12,47.03,45.9
2024-12-05,46.26,46.69,45.96
2024-12-06,47.84,48.32,46.75
2024-12-09,46.9,48.05,46.46
2024-12-10,47.09,48.61,47.0
2024-12-11,47.1,47.44,46.73
2024-12-12,47.18,47.48,46.39
2024-12-13,45.76,47.03,45.75
2024-12-16,45.6,46.3,45.41
2024-12-17,45.78,46.92,45.5
2024-12-18,46.54,47.17,45.2
2024-12-19,51.19,51.19,45.81
2024-12-20,51.56,53.0,50.97
2024-12-23,50.85,53.0,50.26
2024-12-24,53.88,54.23,50.5
2024-12-25,53.86,55.33,52.72
2024-12-26,55.05,56.37,52.31
2024-12-27,53.43,55.55,52.72
2024-12-30,53.07,54.55,52.99
2024-12-31,51.88,54.15,51.6
2025-01-02,48.69,52.1,47.92
2025-01-03,45.88,48.8,45.8
2025-01-06,45.91,47.19,45.36
2025-01-07,48.58,48.74,45.89
2025-01-08,48.03,48.35,46.13
2025-01-09,49.04,49.95,47.55
2025-01-10,46.86,48.84,46.86
2025-01-13,46.63,47.27,46.0
2025-01-14,50.45,50.45,46.0
2025-01-15,50.97,52.23,50.2
2025-01-16,49.85,51.7,49.1
2025-01-17,50.0,51.25,49.01
2025-01-20,50.42,51.2,49.88
2025-01-21,52.33,52.94,50.99
2025-01-22,52.96,54.0,51.71
2025-01-23,51.74,53.91,51.42
2025-01-24,52.96,53.19,51.5
2025-01-27,51.94,55.56,51.73
2025-02-05,55.71,56.98,53.84
2025-02-06,56.28,57.08,54.2
2025-02-07,60.28,61.91,55.7
2025-02-10,60.82,64.46,60.1
2025-02-11,62.9,64.33,60.2
2025-02-12,62.94,65.75,61.62
2025-02-13,60.67,62.38,59.95
2025-02-14,63.27,63.67,60.3
2025-02-17,67.87,69.6,64.7
2025-02-18,63.14,66.47,62.92
2025-02-19,64.57,64.57,62.8
2025-02-20,63.36,64.28,62.22
2025-02-21,67.75,69.0,64.33
2025-02-24,67.13,68.88,66.0
2025-02-25,64.97,66.21,63.88
2025-02-26,65.08,65.99,63.26
2025-02-27,62.8,65.1,61.61
2025-02-28,59.21,62.65,59.0
2025-03-03,58.24,59.8,57.13
2025-03-04,58.81,58.87,57.01
2025-03-05,60.0,60.1,58.23
2025-03-06,61.39,62.0,60.45
2025-03-07,59.88,61.25,59.3
2025-03-10,59.3,60.19,58.79
2025-03-11,58.82,59.09,57.9
2025-03-12,59.49,60.88,58.91
2025-03-13,57.79,59.2,57.5
2025-03-14,59.27,59.5,57.53
2025-03-17,59.37,60.16,58.67
2025-03-18,59.85,60.86,59.5
2025-03-19,59.06,60.2,58.84
2025-03-20,58.3,59.5,58.21
2025-03-21,56.63,58.18,56.5
2025-03-24,57.62,57.85,55.77
2025-03-25,55.43,57.71,55.26
2025-03-26,53.83,54.94,53.58
2025-03-27,53.57,54.16,53.17
2025-03-28,53.54,54.1,53.45
2025-03-31,53.48,53.8,52.22
2025-04-01,53.07,53.88,53.06
2025-04-02,53.08,53.67,52.9
2025-04-03,52.2,53.19,51.88
2025-04-07,46.98,49.06,46.98
2025-04-08,44.63,46.78,43.26
2025-04-09,45.7,46.06,41.57
2025-04-10,47.25,48.44,47.1
2025-04-11,47.78,48.2,46.35
2025-04-14,48.22,49.3,48.08
2025-04-15,48.35,48.79,47.52
2025-04-16,47.19,48.05,46.59
2025-04-17,47.12,48.0,46.8
2025-04-18,47.29,47.6,46.9
2025-04-21,48.69,48.69,46.97
2025-04-22,47.97,48.69,47.8
2025-04-23,48.58,49.13,48.01
2025-04-24,47.75,48.68,47.53
2025-04-25,48.16,48.58,47.85

Indicator data:
date,20日,close
2024-11-18,51.65065603457001,46.92
2024-11-19,51.475095667666395,48.9
2024-11-20,51.30621205060773,48.89
2024-11-21,51.21316934321407,49.26
2024-11-22,50.83811017146356,47.71
2024-11-25,50.27414463475656,46.45
2024-11-26,49.56736881323671,45.29
2024-11-27,49.19127913790426,46.62
2024-11-28,48.96712156568967,47.21
2024-11-29,48.874719366523635,47.8
2024-12-02,48.831054805605184,48.03
2024-12-03,48.51049442983652,46.5
2024-12-04,48.160915578653224,46.12
2024-12-05,47.88163751155167,46.26
2024-12-06,47.924934717288934,47.84
2024-12-09,47.789085629765125,46.9
2024-12-10,47.704283219073154,47.09
2024-12-11,47.63110679472828,47.1
2024-12-12,47.580900181650236,47.18
2024-12-13,47.27856868947841,45.76
2024-12-16,46.988283103464944,45.6
2024-12-17,46.77071795842022,45.78
2024-12-18,46.72150279017798,46.54
2024-12-19,47.52310667476719,51.19
2024-12-20,48.27967487349199,51.56
2024-12-23,48.799952470420976,50.85
2024-12-24,49.79410304323205,53.88
2024-12-25,50.64134101287347,53.86
2024-12-26,51.57995222146543,55.05
2024-12-27,52.08589062830407,53.43
2024-12-30,52.44693417106037,53.07
2024-12-31,52.53226066142497,51.88
2025-01-02,52.017507419647,48.69
2025-01-03,51.05620141066643,45.88
2025-01-06,50.22777448349035,45.91
2025-01-07,49.9948193391717,48.58
2025-01-08,49.691517560360545,48.03
2025-01-09,49.611386012985776,49.04
2025-01-10,49.145143308554424,46.86
2025-01-13,48.70102950008744,46.63
2025-01-14,49.011666228303014,50.45
2025-01-15,49.37332879966948,50.97
2025-01-16,49.48069132362553,49.85
2025-01-17,49.59913827567457,50.0
2025-01-20,49.77592466249319,50.42
2025-01-21,50.27296817041053,52.33
2025-01-22,50.812788654937776,52.96
2025-01-23,51.05284316807743,51.74
2025-01-24,51.4768982850187,52.96
2025-01-27,51.65244545979358,51.94
2025-02-05,52.48265577329599,55.71
2025-02-06,53.29493536531682,56.28
2025-02-07,54.712561649349134,60.28
2025-02-10,56.02147965827945,60.82
2025-02-11,57.51380048048063,62.9
2025-02-12,58.79151616050945,62.94
2025-02-13,59.46328327127673,60.67
2025-02-14,60.49578847286829,63.27
2025-02-17,62.20062118008616,67.87
2025-02-18,62.78956023356757,63.14
2025-02-19,63.534251293369195,64.57
2025-02-20,63.933744416759026,63.36
2025-02-21,65.05193498337283,67.75
2025-02-24,65.87927977841613,67.13
2025-02-25,66.17604701627774,64.97
2025-02-26,66.4279943741075,65.08
2025-02-27,66.20840484730503,62.8
2025-02-28,65.34648775305354,59.21
2025-03-03,64.40930402961362,58.24
2025-03-04,63.689574913331846,58.81
2025-03-05,63.27202273503015,60.0
2025-03-06,63.15269296789401,61.39
2025-03-07,62.76509927672004,59.88
2025-03-10,62.31643324583414,59.3
2025-03-11,61.83472310947781,58.82
2025-03-12,61.534595554687456,59.49
2025-03-13,60.961977800723574,57.79
2025-03-14,60.73294623522731,59.27
2025-03-17,60.5503335819732,59.37
2025-03-18,60.477216797046616,59.85
2025-03-19,60.268364129140295,59.06
2025-03-20,59.94856986693906,58.3
2025-03-21,59.368887308838374,56.63
2025-03-24,59.04911190586854,57.62
2025-03-25,58.37710426846358,55.43
2025-03-26,57.510022240851235,53.83
2025-03-27,56.719689585677855,53.57
2025-03-28,56.03871714381775,53.54
2025-03-31,55.447728662895386,53.48
2025-04-01,54.87172468043607,53.07
2025-04-02,54.38568310132143,53.08
2025-04-03,53.816332211376604,52.2
2025-04-07,52.388665544447825,46.98
2025-04-08,50.744623982227694,44.63
2025-04-09,49.53746411853069,45.7
2025-04-10,48.79566237869227,47.25
2025-04-11,48.27055335919921,47.78
2025-04-14,47.91607134225184,48.22
2025-04-15,47.65223394205454,48.35
2025-04-16,47.232156306590966,47.19
2025-04-17,46.87520244802245,47.12
2025-04-18,46.616061512114676,47.29
2025-04-21,46.66401134451566,48.69
2025-04-22,46.59102686405919,47.97
2025-04-23,46.65444748786639,48.58
2025-04-24,46.57326167209072,47.75
2025-04-25,46.59185322269532,48.16

Answer: 4.0