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 A242657 #7 May 30 2014 18:09:12 %S A242657 15,101,359,961,2191,4489,8504,15159,25728,41926,66013,100913,150349, %T A242657 218995,312646,438407,604902,822504,1103587,1462801,1917371,2487421, %U A242657 3196324,4071079,5142716,6446730,8023545,9919009,12184921,14879591,18068434,21824599,26229634,31374188,37358751,44294433,52303783,61521649 %N A242657 Mahonian numbers T(n,7) (cf. A008302). %C A242657 45 years ago this was A000712, but it was dropped during the preparation of the 1973 Handbook of Integer Sequences. %p A242657 g := proc(n, k) option remember; if k=0 then return(1) else if (n=1 and k=1) then return(0) else if (k<0 or k>binomial(n, 2)) then return(0) else g(n-1, k)+g(n, k-1)-g(n-1, k-n) end if end if end if end proc; %p A242657 [seq(g(n,7),n=5..40)]; %Y A242657 Cf. A008302. %K A242657 nonn %O A242657 5,1 %A A242657 _N. J. A. Sloane_, May 30 2014