Even rounded factorial: product(k in [1, n - 1]: ceil(n / k) - ceil(n / k) mod 2).
1, 2, 4, 16, 32, 96, 384, 1024, 2048, 10240, 30720, 73728, 294912, 688128, 1835008
2 seqfan posts
Sun Jun 13 08:51:05 CEST 2010 [seqfan] Re: (3^n+1)/2 is prime, A171381