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

Author

Juri-Stepan Gerasimov, Mar 11 2010

Keywords

• nonn

Comments

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

Examples

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

Crossrefs

Cf. A000040, A163300.

Programs

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

Extensions

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