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 A077490 #5 Dec 05 2013 19:55:52 %S A077490 25,5,3,1,8,6,4,2,9,7,14,12,19,17,24,22,47,72,97,122,147,172,197,222, %T A077490 247,497,747,997,1247,1497,1747,1997,2247,2497,4997,7497,9997,12497, %U A077490 14997,17497,19997,22497,24997,49997,74997,99997,124997,149997,174997 %N A077490 a(n) = smallest k such that 4k has a digit sum = n. %F A077490 A077489(n)/4 %Y A077490 Cf. A077489, A069532, A069534. %K A077490 base,nonn %O A077490 1,1 %A A077490 _Amarnath Murthy_, Nov 07 2002 %E A077490 Corrected and extended by _Sascha Kurz_, Feb 10 2003