A171562 Numbers k such that the k-th non-single or nonisolated number is prime.

1, 6, 8, 10, 11, 13, 15, 16, 17, 18, 21, 22, 23, 26, 27, 28, 29, 33, 34, 36, 38, 39, 40, 42, 44, 45, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 63, 64, 65, 66, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 81, 82, 83, 85, 86, 88, 90, 91, 93, 94, 95, 96, 97, 98, 99, 100

Offset: 1

Author

Juri-Stepan Gerasimov, Dec 11 2009

Keywords

• nonn

Crossrefs

Cf. A000040 (the prime numbers), A167706 (the single or isolated numbers).

Programs

Maple

A167706 := proc(n) if n = 1 then 2; else for a from procname(n-1)+1 do if isA007510(a) or isA014574(a) then return a; end if; end do; end if; end proc:
for n from 1 to 110 do p := A167706(n) ; if isprime(p) then printf("%d,",n) : end if; end do: # R. J. Mathar, May 23 2010

Extensions

Corrected (20 replaced with 18, 25 replaced with 23, 32 replaced with 29, etc.) by R. J. Mathar, May 23 2010