A174185 Numbers k such that the k-th prime minus the k-th even nonprime is prime.

1, 7, 8, 9, 12, 15, 19, 20, 21, 23, 24, 25, 30, 32, 33, 34, 35, 36, 37, 39, 41, 42, 45, 46, 48, 51, 56, 63, 67, 71, 75, 78, 81, 82, 85, 86, 88, 89, 90, 96, 102, 107, 112, 115, 116, 117, 120, 121, 123, 126, 128, 132, 135, 137, 146, 150, 152, 153, 156, 158, 159, 163, 164

Offset

1,2

Comments

Numbers k such that prime(k) - (even nonprime)(k) is prime.

Links

Table of n, a(n) for n=1..63.

Example

1 is a term because A000040(1) - A163300(1) = 2 (prime);
7 is a term because A000040(7) - A163300(7) = 3 (prime).

Maple

A163300 := proc(n) option remember ; if n = 1 then 0; else for a from procname(n-1)+2 by 2 do if not isprime(a) then return a ; end if; end do; end if; end proc:
for n from 1 to 300 do if isprime( ithprime(n) - A163300(n)) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Apr 20 2010

Crossrefs

Cf. A000040, A163300.

Sequence in context: A192050 A045158 A074328 * A309152 A170933 A297257

Adjacent sequences: A174182 A174183 A174184 * A174186 A174187 A174188

Keyword

nonn

Author

Juri-Stepan Gerasimov, Mar 11 2010

Extensions

Corrected (11 replaced with 12) by R. J. Mathar, Apr 20 2010

Status

approved