cp's OEIS Frontend

A026629 a(n) = A026626(2*n, n-2).

%I A026629 #9 Jun 20 2024 11:07:58
%S A026629 1,9,40,171,703,2839,11346,45066,178330,704038,2775590,10933363,
%T A026629 43048403,169463371,667090762,2626243774,10340952238,40727191246,
%U A026629 160443432712,632240809054,2492136145078,9826353817510,38756552628820
%N A026629 a(n) = A026626(2*n, n-2).
%H A026629 G. C. Greubel, <a href="/A026629/b026629.txt">Table of n, a(n) for n = 2..1000</a>
%F A026629 a(n) = ((357*n^5 - 1982*n^4 + 3893*n^3 - 3472*n^2 + 1336*n + 120)*a(n-1) + 2*(2*n-5)*(51*n^4 - 152*n^3 + 129*n^2 - 4*n - 36)*a(n-2))/(2*(n+2)*(51*n^4 - 356*n^3 + 891*n^2 - 922*n + 300)), for n >= 4, with a(2) = 1, a(3) = 9. - _G. C. Greubel_, Jun 20 2024
%t A026629 a[n_]:= a[n]= If[n<4, 8*n-15, ((357*n^5 -1982*n^4 +3893*n^3 -3472*n^2 + 1336*n +120)*a[n-1] + 2*(2*n-5)*(51*n^4 -152*n^3 +129*n^2 -4*n -36)*a[n-2])/(2*(n+2)*(51*n^4 -356*n^3 +891*n^2 -922*n +300))];
%t A026629 Table[a[n], {n,2,41}] (* _G. C. Greubel_, Jun 20 2024 *)
%o A026629 (Magma)
%o A026629 [n le 2 select 8*n-7 else ((357*n^5 -197*n^4 -465*n^3 -115*n^2 -72*n + 252)*Self(n-1) +2*(2*n-3)*(51*n^4 +52*n^3 -21*n^2 +2*n -12)*Self(n-2))/(2*(n+3)*(51*n^4-152*n^3+129*n^2-4*n-36)): n in [1..41]]; // _G. C. Greubel_, Jun 20 2024
%o A026629 (SageMath)
%o A026629 @CachedFunction
%o A026629 def a(n): # a = A026629
%o A026629     if n<4: return 8*n-15
%o A026629     else: return ((357*n^5 -1982*n^4 +3893*n^3 -3472*n^2 +1336*n + 120)*a(n-1) +2*(2*n-5)*(51*n^4 -152*n^3 +129*n^2 -4*n -36)*a(n-2) )/(2*(n+2)*(51*n^4-356*n^3+891*n^2-922*n+300))
%o A026629 [a(n) for n in range(2,41)] # _G. C. Greubel_, Jun 20 2024
%Y A026629 Cf. A026626, A026627, A026628, A026630, A026631, A026632, A026633.
%Y A026629 Cf. A026634, A026635, A026636, A026961, A026962, A026963, A026964.
%Y A026629 Cf. A026965.
%K A026629 nonn
%O A026629 2,2
%A A026629 _Clark Kimberling_