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 A239592 #21 Feb 20 2023 11:11:57
%S A239592 1,3,13,46,129,301,613,1128,1921,3079,4701,6898,9793,13521,18229,
%T A239592 24076,31233,39883,50221,62454,76801,93493,112773,134896,160129,
%U A239592 188751,221053,257338,297921,343129,393301,448788,509953,577171,650829,731326,819073,914493
%N A239592 a(n) = (n^4 - n^3 + 4*n^2 + 2)/2.
%C A239592 Main diagonal of square array A239331.
%H A239592 Vincenzo Librandi, <a href="/A239592/b239592.txt">Table of n, a(n) for n = 0..1000</a>
%H A239592 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A239592 G.f.: (1 - 2*x + 8*x^2 + x^3 + 4*x^4)/(1-x)^5.
%F A239592 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5), a(0) = 1, a(1) = 3, a(2) = 13, a(3) = 46, a(4) = 129.
%F A239592 a(n) = A058331(n) + A092364(n).
%t A239592 CoefficientList[Series[(1 - 2 x + 8 x^2 + x^3 + 4 x^4)/(1 - x)^5, {x, 0, 40}], x] (* _Vincenzo Librandi_, Mar 23 2014 *)
%o A239592 (PARI) Vec((1-2*x+8*x^2+x^3+4*x^4)/(1-x)^5 + O(x^100)) \\ _Colin Barker_, Mar 22 2014
%o A239592 (Magma) [(n^4-n^3+4*n^2 + 2)/2: n in [0..40]]; // _Vincenzo Librandi_, Mar 23 2014
%Y A239592 Cf. A239331.
%K A239592 nonn,easy
%O A239592 0,2
%A A239592 _Philippe Deléham_, Mar 22 2014