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 A254229 #8 Sep 19 2022 13:41:15
%S A254229 1,46,207,14652,66493,4717738,21410379,1519096824,6894075385,
%T A254229 489144459430,2219870863431,157502996839476,714791523949237,
%U A254229 50715475837851682,230160650840790723,16330225716791401968,74111014779210663409,5258281965330993581854
%N A254229 Indices of centered square numbers (A001844) which are also heptagonal numbers (A000566).
%C A254229 Also positive integers y in the solutions to 5*x^2 - 4*y^2 - 3*x + 4*y - 2 = 0, the corresponding values of x being A254228.
%H A254229 Colin Barker, <a href="/A254229/b254229.txt">Table of n, a(n) for n = 1..797</a>
%H A254229 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,322,-322,-1,1).
%F A254229 a(n) = a(n-1)+322*a(n-2)-322*a(n-3)-a(n-4)+a(n-5).
%F A254229 G.f.: x*(45*x^3+161*x^2-45*x-1) / ((x-1)*(x^2-18*x+1)*(x^2+18*x+1)).
%e A254229 46 is in the sequence because the 46th centered square number is 4141, which is also the 41st heptagonal number.
%t A254229 LinearRecurrence[{1,322,-322,-1,1},{1,46,207,14652,66493},20] (* _Harvey P. Dale_, Sep 19 2022 *)
%o A254229 (PARI) Vec(x*(45*x^3+161*x^2-45*x-1)/((x-1)*(x^2-18*x+1)*(x^2+18*x+1)) + O(x^100))
%Y A254229 Cf. A000566, A001844, A254228, A254230.
%K A254229 nonn,easy
%O A254229 1,2
%A A254229 _Colin Barker_, Jan 27 2015