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 A117489 #5 Mar 31 2012 13:23:38 %S A117489 1,6,30,115,374,1079,2848,7005,16285,36117,76981,158563,317014,617349, %T A117489 1174400,2187584,3998057,7181362,12696179,22120549,38023748,64546190, %U A117489 108296742,179729895,295244362,480358370,774483006,1238052200 %N A117489 Row sums of A117488 which has 1, 3, 5, 7, ... entries per row. %C A117489 Note that the central diagonal of table A117488 is 1 2 5 20 ... %e A117489 A117488 begins %e A117489 1 %e A117489 1 2 3 %e A117489 1 2 5 8 14 %e A117489 1 2 5 10 18 30 49 %e A117489 1 2 5 10 20 34 59 94 149 %e A117489 so a(n) begins %e A117489 1 6 30 115 374 ... %Y A117489 Cf. A115994, A117488. %K A117489 nonn %O A117489 1,2 %A A117489 _Alford Arnold_, Mar 22 2006 %E A117489 More terms from _David Wasserman_, Nov 03 2010