Numbers n such that both A000203(n)-n-1 and A000203(n)-2*n-1 are prime numbers, and sigma(n)-2*n-1 > 5.
30, 42, 60, 78, 102, 138, 186, 198, 216, 222, 228, 240, 246, 258, 270, 282, 360, 372
2 seqfan posts
Tue Aug 24 03:37:54 CEST 2010 [seqfan] Re: A180268