A179945 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, 390, 414, 438, 492, 498, 546, 582, 600, 606, 642, 708, 720, 756, 762, 774, 786, 810, 852, 870, 930, 942, 954, 1002, 1014, 1020, 1026, 1038, 1068, 1086, 1182, 1266, 1290

Offset: 1

Author

Alexey Galkin (fetch91(AT)gmail.com), Aug 03 2010

Keywords

• nonn

Comments

The smallest term that is not multiple of 6 is 3472.

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A175727.

Programs

PARI

is(n)=my(s=sigma(n));s>2*n+6 && isprime(s-n-1) && isprime(s-n-n-1) \\ Charles R Greathouse IV, Feb 19 2013