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 A105839 #13 Jun 13 2015 00:51:47 %S A105839 1,37,2927,68171,183769,4280053,338355383,7880431259,21243328861, %T A105839 494765566657,39113205561107,910962092609711,2455686329490109, %U A105839 57193909970135833,4521408336114491603,105305395973616940919,283872428295154291321,6611501604232996456477 %N A105839 Numbers n such that n^2 = 19*m^2 + 19*m + 1. %H A105839 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,115598,0,0,0,-1). %F A105839 Define a(1)=0, a(2)=39, a(3)=2927, a(4)=68171, a(5)=115598*a(1)+a(4), a(6)=115598*a(2)+a(3), a(7)=115598*a(3)+a(2), a(8)=115598*a(4)+a(1) then a(n)=115598*a(n-4)-a(n-8). %F A105839 G.f.: x*(x+1)*(x^6+36*x^5+2891*x^4+65280*x^3+2891*x^2+36*x+1) / ((x^4-340*x^2+1)*(x^4+340*x^2+1)). - _Colin Barker_, Mar 06 2013 %Y A105839 Cf. A101180 (associated m). %K A105839 nonn,easy %O A105839 1,2 %A A105839 _Pierre CAMI_, Apr 22 2005 %E A105839 a(13)-a(18) from _Colin Barker_, Mar 06 2013