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 A087306 #8 Dec 05 2013 19:56:20 %S A087306 1,3,155,111,3875983,1333,763274553951,11978 %N A087306 a(n) is the start of the first arithmetic progression with common difference n of n numbers with the same prime signature. %C A087306 First column of A087307; main diagonal of A114656. %C A087306 a(7) > 29*10^9; a(8) = 11978. %C A087306 a(n) > 10^10 for n from 9 to 11. a(12) = 120998. [From _Donovan Johnson_, Oct 24 2009] %e A087306 a(4) = 111 as 111, 115, 119 and 123 all are of the prime signature p*q. %Y A087306 Cf. A087307, A114656. %K A087306 nonn,hard %O A087306 1,2 %A A087306 _Amarnath Murthy_, Sep 02 2003 %E A087306 Edited and extended by _David Wasserman_, Jan 08 2006 %E A087306 a(7) from _Donovan Johnson_, Oct 24 2009