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 A205136 #5 Mar 30 2012 18:58:10 %S A205136 4,11,7,21,17,10,34,30,23,13,50,46,39,29,16,69,65,58,48,35,19,91,87, %T A205136 80,70,57,41,22,116,112,105,95,82,66,47,25,144,140,133,123,110,94,75, %U A205136 53,28,175,171,164,154,141,125,106,84,59,31,209,205,198,188,175 %N A205136 Ordered differences of distinct pentagonal numbers. %C A205136 For a guide to related sequences, see A204892. %e A205136 a(1)=s(2)-s(1)=5-1=4 %e A205136 a(2)=s(3)-s(1)=12-1=11 %e A205136 a(3)=s(3)-s(2)=12-5=7 %e A205136 a(4)=s(4)-s(1)=22-1=21 %e A205136 a(5)=s(4)-s(2)=22-5=17 %t A205136 (See the program at A205138.) %Y A205136 Cf. A205138, A204892. %K A205136 nonn %O A205136 1,1 %A A205136 _Clark Kimberling_, Jan 25 2012