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 A073217 #3 Mar 30 2012 17:24:45 %S A073217 1,3,5,13,15,25,63,65,75,125,313,315,325,375,625,1563,1565,1575,1625, %T A073217 1875,3125,7813,7815,7825,7875,8125,9375,15625,39063,39065,39075, %U A073217 39125,39375,40625,46875,78125 %N A073217 The terms of A055237 (sums of two powers of 5) divided by 2. %F A073217 (5^n + 5^m) / 2, n = 0, 1, 2, 3 ..., m = 0, 1, 2, 3, ... n. %e A073217 a(4) = 13 = (5^2+5^0) / 2 %Y A073217 Cf. A055237. %K A073217 easy,nonn %O A073217 1,2 %A A073217 _Jeremy Gardiner_, Jul 21 2002