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 A107736 #17 Sep 02 2024 08:38:47
%S A107736 35,46651605,62126595542551,82734857056306152425,
%T A107736 110179167429819564875005515,146727139774551997160896788291901,
%U A107736 195398586217617559179696685958485684415,260215032846061623065656040447357907946787025,346532002251364709713039450689133092337489050568051
%N A107736 Pentagonal numbers that are half other pentagonal numbers.
%H A107736 Colin Barker, <a href="/A107736/b107736.txt">Table of n, a(n) for n = 1..163</a>
%H A107736 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1331715,-1331715,1).
%F A107736 a(n) = (A001653(4*n-1)^2-1)/24.
%F A107736 G.f.: -x*(x^2+41580*x+35) / ((x-1)*(x^2-1331714*x+1)). - _Colin Barker_, Jun 18 2015
%e A107736 a(2) = (A001653(7)^2-1)/24 = (33461^2-1)/24 = 46651605.
%t A107736 LinearRecurrence[{1331715,-1331715,1},{35,46651605,62126595542551},20] (* _Harvey P. Dale_, Aug 04 2020 *)
%o A107736 (PARI) Vec(-x*(x^2+41580*x+35)/((x-1)*(x^2-1331714*x+1)) + O(x^20)) \\ _Colin Barker_, Jun 18 2015
%Y A107736 Cf. A001653, A000326.
%K A107736 nonn,easy
%O A107736 1,1
%A A107736 _Franz Vrabec_, Aug 26 2006