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 A348621 #17 Oct 28 2021 06:31:58
%S A348621 0,4,21,82,275,836,2373,6406,16647,41992,103433,249866,593931,1392652,
%T A348621 3227661,7405582,16842767,38010896,85196817,189792274,420478995,
%U A348621 926941204,2034237461,4445962262,9680453655,21005074456,45432700953,97978941466,210721832987,452045307932
%N A348621 The number of additions required to compute the permanent of general n X n matrices using Ryser's formula without Gray code ordering.
%D A348621 Herbert John Ryser, Combinatorial Mathematics, volume 14 of Carus Mathematical Monographs. American Mathematical Soc., (1963), pp. 24-28.
%H A348621 Han Mao Kiah, Alexander Vardy and Hanwen Yao, <a href="https://arxiv.org/abs/2107.07377">Computing Permanents on a Trellis</a>, arXiv:2107.07377 [cs.IT], 2021. See Table 1 p. 3.
%H A348621 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (8,-25,38,-28,8).
%F A348621 a(n) = (n^2 - 2*n + 2)*2^(n-1) + n - 2.
%F A348621 a(n) = n*A000337(n-1) + A000079(n) - 2.
%F A348621 a(n) = 8*a(n-1) - 25*a(n-2) + 38*a(n-3) - 28*a(n-4) + 8*a(n-5) for n > 5.
%F A348621 O.g.f.: x^2*(4 - 11*x + 14*x^2 - 8*x^3)/((1 - x)^2*(1 - 2*x)^3).
%F A348621 E.g.f.: 1 + exp(x)*(x - 2) + exp(2*x)*(2*x^2 - x + 1).
%t A348621 LinearRecurrence[{8,-25,38,-28,8},{0,4,21,82,275},30]
%Y A348621 Cf. A000079, A000337, A059672, A160457.
%K A348621 nonn,easy
%O A348621 1,2
%A A348621 _Stefano Spezia_, Oct 25 2021