A231988 - OEIS

%I #5 Nov 19 2013 13:20:40

%S 7,29,67,191,277,947,1129,2557,5779,8647,13367,14029,16111,22367,

%T 24977,31627,36857,47279,64621,87991,93097,96581,98347,109279,126757,

%U 163307,239087,282377,329267,342379,352381,372817,411779,448879,468029,471907,491537,519691,531997

%N Primes of the form triangular(p) + 1, where p is a prime.

%C Triangular(p) = p*(p+1)/2.

%F a(n) = A000217(A231847(n))+1.

%t t = Select[Prime[Range[300]], PrimeQ[# (# + 1)/2 + 1] &]; t*(t + 1)/2 + 1 (* _T. D. Noe_, Nov 19 2013 *)

%Y Cf. A000040, A000217, A231847.

%K nonn

%O 1,1

%A _Alex Ratushnyak_, Nov 16 2013