%I
%S 1,3,5,8,10,16,19,20,23,51,54,58,70,71,103,136,139,142,145,153,161,
%T 168,169,182,204,212,219,222,224,230,232,235,240,242,276,277,286
%N Rows of A217916 in which 2's appear, when A217916 is formed into a number triangle.
%C The number 2 appears only in column 1 of A217916 (when treated as a triangle).
%F Involves triangularindexed twin primes:
%F prime(a(n)*(a(n)1)/2 + 1)  prime(a(n)*(a(n)1)/2) = 2 for n>1 with a(1)=1.
%Y Cf. A217916, A217918.
%K nonn
%O 1,2
%A _Paul D. Hanna_, Mar 04 2013
