I dont think its equivalent to the sieve of eratosthenes even when the optimization of using only odds is used Here is what Sieve of Sundaram looks like where we loop at a  i   and b  j   instead of i and j  n    limit   initialize the sieve isprime  true isprimei  i is odd  i   n  for all odd a such that   a and a  n     for all odd b such that a  b and ab  n         isprimeab  false   while Sieve of Eratosthenes using only odd integers roughly looks like this only one line is added  n    limit   initialize the sieve isprime  true isprimei  i is odd  i   n  for all odd a such that   a and a  n     if not isprimea continue       only this has changed     for all odd b such that a  b and ab  n         isprimeab  false   This also shows that the Sieve of Sundaram is less efficient than the Sieve of Eratosthenes and that its complexity is n log n since         n grows asymptotically as log n compared to sieve of eratosthenes n log log n since           p grows asymptotically as log log n