Prefer strconv.FormatInt/FormatUint/Itoa to sprintf when you just want to print a number.  

To double check myself, I benchmarked this routine using both, expanding a 1000-length list and found it to be 4x faster 

BenchmarkStrconv	   20000	     85257 ns/op	   46904 B/op	    1003 allocs/op
BenchmarkSprintf	   10000	    264648 ns/op	   46904 B/op	    1003 allocs/op