%I #4 Mar 30 2012 18:56:05
%S 1,5,2,3,9,10,4,13,14,6,17,18,7,8,22,26,27,11,30,31,12,34,35,39,15,16,
%T 43,47,48,19,51,52,20,21,56,60,23,24,64,65,25,68,69,73,28,29,77,81,82,
%U 32,85,86,33,89,90,94,36,37,98,99,38,102,103
%N a(n) = (1/2)*s(n), where s(n) is n-th even number in A002251.
%K nonn
%O 1,2
%A _Clark Kimberling_