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 A259403 #7 Jan 21 2017 15:45:43
%S A259403 2882,27676,1114135,10982301,443390277,4370895551,176468183540,
%T A259403 1739605414426,70233893626072,692358584013426,27952913194960545,
%U A259403 275556976831896551,11125189217700638267,109670984420510781301,4427797355731659037150,43648776242386459028676
%N A259403 Pentagonal numbers (A000326) that are the sum of eleven consecutive pentagonal numbers.
%H A259403 Colin Barker, <a href="/A259403/b259403.txt">Table of n, a(n) for n = 1..767</a>
%H A259403 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,398,-398,-1,1).
%F A259403 G.f.: -11*x*(16*x^4+14*x^3-5507*x^2+2254*x+262) / ((x-1)*(x^2-20*x+1)*(x^2+20*x+1)).
%e A259403 2882 is in the sequence because P(44) = 2882 = 92 + 117 + 145 + 176 + 210 + 247 + 287 + 330 + 376 + 425 + 477 = P(8)+ ... +P(18).
%t A259403 LinearRecurrence[{1,398,-398,-1,1},{2882,27676,1114135,10982301,443390277},30] (* _Harvey P. Dale_, Jan 21 2017 *)
%o A259403 (PARI) Vec(-11*x*(16*x^4+14*x^3-5507*x^2+2254*x+262)/((x-1)*(x^2-20*x+1)*(x^2+20*x+1)) + O(x^20))
%Y A259403 Cf. A000326, A133301, A257714, A257715, A259402, A259404.
%K A259403 nonn,easy
%O A259403 1,1
%A A259403 _Colin Barker_, Jun 26 2015