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 A073373 #17 Sep 30 2022 01:45:37
%S A073373 1,4,18,60,195,576,1644,4488,11925,30860,78278,195012,478599,1159080,
%T A073373 2774880,6575280,15439065,35955540,83118970,190862860,435601611,
%U A073373 988620624,2232236628,5016441240,11224087965
%N A073373 Third convolution of A001045(n+1) (generalized (1,2)-Fibonacci), n>=0, with itself.
%H A073373 G. C. Greubel, <a href="/A073373/b073373.txt">Table of n, a(n) for n = 0..1000</a>
%H A073373 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (4,2,-20,-1,40,8,-32,-16).
%F A073373 a(n) = Sum_{k=0..n} b(k) * c(n-k), with b(k) = A001045(k+1) and c(k) = A073372(k).
%F A073373 a(n) = Sum_{k=0..floor(n/2)} binomial(n-k+3, 3) * binomial(n-k, k) * 2^k.
%F A073373 a(n) = ((350+177*n+21*n^2)*(n+1)*U(n+1) + 2*(277+132*n+15*n^2)*(n+2)*U(n))/ (2*9^3) with U(n) = A001045(n+1), n>=0.
%F A073373 G.f.: 1/(1-(1+2*x)*x)^4 = 1/ ( (1+x)^4*(1-2*x)^4 ).
%F A073373 E.g.f.: (1/4374)*(32*(113 + 366*x + 234*x^2 + 36*x^3)*exp(2*x) - (-758 + 690*x - 153*x^2 + 9*x^3)*exp(-x)). - _G. C. Greubel_, Sep 29 2022
%t A073373 Table[(1/4374)*(2^(n+4)*(226 +267*n +90*n^2 +9*n^3) +(-1)^n*(758 +555*n +126*n^2 +9*n^3)), {n,0,40}] (* _G. C. Greubel_, Sep 29 2022 *)
%o A073373 (Magma) [(1/4374)*(2^(n+4)*(226 +267*n +90*n^2 +9*n^3) +(-1)^n*(758 +555*n +126*n^2 +9*n^3)): n in [0..40]]; // _G. C. Greubel_, Sep 29 2022
%o A073373 (SageMath)
%o A073373 def A073373(n): return (1/4374)*(2^(n+4)*(226+267*n+90*n^2+9*n^3) +(-1)^n*(758 +555*n+126*n^2+9*n^3))
%o A073373 [A073373(n) for n in range(40)] # _G. C. Greubel_, Sep 29 2022
%Y A073373 Fourth (m=3) column of triangle A073370.
%Y A073373 Cf. A001045, A073372.
%K A073373 nonn,easy
%O A073373 0,2
%A A073373 _Wolfdieter Lang_, Aug 02 2002