This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A025720 #7 Jul 06 2025 14:08:05 %S A025720 1,4,10,19,31,46,63,83,106,132,161,192,226,263,303,346,391,439,490, %T A025720 544,601,660,722,787,855,926,999,1075,1154,1236,1321,1409,1499,1592, %U A025720 1688,1787,1889,1993,2100,2210,2323,2439,2557,2678,2802,2929,3059,3191,3326 %N A025720 Index of 7^n within sequence of numbers of form 2^i*7^j. %C A025720 Positions of zeros in A025637. - _R. J. Mathar_, Jul 06 2025 %K A025720 nonn %O A025720 1,2 %A A025720 _David W. Wilson_