A055453 a(n) = T(n,n-3), array T as in A055450.

1, 4, 9, 14, 56, 230, 965, 4120, 17846, 78244, 346605, 1549030, 6976140, 31628838, 144250962, 661352970, 3046379300, 14091723450, 65432979080, 304880016970, 1425043805000, 6680031216850, 31396257423925, 147923222356036

Offset: 3

Author

Clark Kimberling, May 18 2000

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 3..500

Crossrefs

Cf. A055450, A055451, A055452, A055454, A055455.

Programs

Magma

[n le 6 select (n-2)^2 else Round(14*HypergeometricSeries2F1(6-n,9/2,6,-4)): n in [3..40]]; // G. C. Greubel, Jan 30 2024

Mathematica

Table[If[n<6, (n-2)^2, 14*Hypergeometric2F1[6-n,9/2,6,-4]], {n,3,40}] (* G. C. Greubel, Jan 30 2024 *)

SageMath

def A055453(n): return (n-2)^2 if n<6 else 14*hypergeometric([6-n,9/2],[6],-4).simplify()
[A055453(n) for n in range(3,41)] # G. C. Greubel, Jan 30 2024

Formula

a(n) = 14*Hypergeometric2F1([6-n, 9/2], [6], -4), for n >= 6 and a(n) = (n-2)^2 for 3 <= n <= 5. - G. C. Greubel, Jan 30 2024