%I #5 Mar 30 2012 18:35:26
%S 1,4,10,19,31,46,63,83,106,132,161,192,226,263,303,346,391,439,490,
%T 544,601,660,722,787,855,926,999,1075,1154,1236,1321,1409,1499,1592,
%U 1688,1787,1889,1993,2100,2210,2323,2439,2557,2678,2802,2929,3059,3191,3326
%N Index of 7^n within sequence of numbers of form 2^i*7^j.
%K nonn
%O 1,2
%A _David W. Wilson_