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 A256403 #9 Apr 05 2015 12:01:47 %S A256403 1,2,4,8,12,16,21,24,69,201,213,319,469,519,1141,2321,39203,72899, %T A256403 324899,359999,675683,777923,1127843,4536899,6718463,10036223, %U A256403 30272003,44916803,54022499,100761443,108743183,110249999,212051843,233722943,289952783,326163599 %N A256403 Records in A166133. %C A256403 See the "blog" file in A166133 for discussion. %H A256403 John Mason, <a href="/A256403/b256403.txt">Table of n, a(n) for n = 1..142</a> %Y A256403 Cf. A166133, A256404. %K A256403 nonn %O A256403 1,2 %A A256403 _N. J. A. Sloane_, Apr 01 2015