%I A075402
%S A075402 1,0,1,1,2,2,1,1,2,4,1,1,6,2,7,1,4,2,1,1,2,4,1,7,6,2,1,3,4,2,3,13,2,4,
%T A075402 1,7,6,2,7,1,2,4,1,1,4,6,1,5,4,2,1,3,2,2,3,1,4,10,7,1,10,20,1,1,8,2,3,
%U A075402 1,2,18,1,5,6,2,1,1,8,2,3,11,2,4,5,1,4,20,5,1,2,4,15,5,2,16,1,1,6,10,1
%N A075402 Smallest number such that a(n) + T(n) is a prime, where T(n) is the n-th 
               triangular number.
%C A075402 0 occurs only once in this sequence.
%o A075402 (PARI) for(n=1,100,a=n*(n+1)/2:print1(nextprime(a)-a","))
%Y A075402 Cf. A075403.
%Y A075402 Sequence in context: A156282 A120423 A113137 this_sequence A088855 A034851 
               A122085
%Y A075402 Adjacent sequences: A075399 A075400 A075401 this_sequence A075403 A075404 
               A075405
%K A075402 nonn
%O A075402 1,5
%A A075402 Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 23 2002
%E A075402 Corrected and extended by Ralf Stephan (ralf(AT)ark.in-berlin.de), Mar 
               19 2003