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 A304578 #11 Sep 08 2022 08:46:21
%S A304578 3,19,179,1547,12083,87811,605827,4017787,25823651,161789939,
%T A304578 992351123,5978820331,35477981011,207792160483,1203339605987,
%U A304578 6900229858139,39226193944643,221290021193683,1239902910407539,6905023951693771,38243741775219827,210766657862250179,1156345359837548099
%N A304578 a(n) = (n^2 + 1) * 5^n + (n^2 + 2) * 3^n.
%H A304578 Daniele Mastrostefano and Carlo Sanna, <a href="https://arxiv.org/abs/1805.05114">On numbers n with polynomial image coprime with the nth term of a linear recurrence</a>, arXiv:1805.05114 [math.NT], 2018 (see 4.2, page 7).
%H A304578 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (24,-237,1232,-3555,5400,-3375).
%F A304578 G.f.: (3-53*x+434*x^2-1942*x^3+4635*x^4-4725*x^5)/((1-5*x)^3(1-3*x)^3).
%t A304578 CoefficientList[Series[(3 - 53 x + 434 x^2 - 1942 x^3 + 4635 x^4 - 4725 x^5)/((1-5 x)^3(1-3 x)^3), {x, 0, 33}], x] (* or *) Table[(n^2 + 1) 5^n + (n^2 + 2) 3^n, {n, 0, 20}]
%o A304578 (Magma) [(n^2+1)*5^n+(n^2+2)*3^n: n in [0..25]];
%o A304578 (PARI) a(n)=(n^2+1)*5^n+(n^2+2)*3^n \\ _Charles R Greathouse IV_, May 16 2018
%K A304578 nonn,easy
%O A304578 0,1
%A A304578 _Vincenzo Librandi_, May 16 2018