A055452 a(n) = T(n,n-2), array T as in A055450.

1, 3, 5, 19, 75, 305, 1270, 5390, 23236, 101480, 448085, 1997115, 8973255, 40602093, 184853055, 846206025, 3892585325, 17984308775, 83417287855, 388297304825, 1813341109825, 8493372326675, 39889629750600

Offset: 2

Author

Clark Kimberling, May 18 2000

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 2..500

Crossrefs

Cf. A055450, A055451, A055453, A055454, A055455.

Programs

Magma

[n le 3 select 2*n-3 else Round(5*HypergeometricSeries2F1(4-n,7/2,5,-4)): n in [2..40]]; // G. C. Greubel, Jan 29 2024

Mathematica

Table[If[n<4, 2*n-3, 5*Hypergeometric2F1[4-n,7/2,5,-4]], {n,2,40}] (* G. C. Greubel, Jan 29 2024 *)

SageMath

def A055452(n): return 2*n-3 if n<4 else 5*hypergeometric([4-n,7/2],[5],-4).simplify()
[A055452(n) for n in range(2,41)] # G. C. Greubel, Jan 29 2024

Formula

a(n) = 5*hypergeometric([4-n,7/2],[5],-4), for n>3. - Peter Luschny, Aug 15 2012