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 A087307 #5 Dec 05 2013 19:56:20 %S A087307 1,3,5,155,158,161,111,115,119,123,3875983,3875988,3875993,3875998, %T A087307 3876003,1333,1339,1345,1351,1357,1363 %N A087307 Triangle read by rows: n-th row is the first arithmetic progression with common difference n of n numbers with the same prime signature. %e A087307 Triangle begins: %e A087307 1, %e A087307 3,5, %e A087307 155,158,161, %e A087307 111,115,119,123, %e A087307 3875983,3875988,3875993,3875998,3876003 %e A087307 ... %Y A087307 Cf. A087306. %K A087307 nonn,tabl %O A087307 1,2 %A A087307 _Amarnath Murthy_, Sep 02 2003 %E A087307 Edited and extended by _David Wasserman_, Jan 08 2006