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A055817 a(n) = T(2n+5,n), array T as in A055807. 7
1, 63, 448, 2816, 16896, 99200, 575872, 3322112, 19096064, 109541824, 627653440, 3594256896, 20577979392, 117814911744, 674630384384, 3864033226240, 22138650598400, 126885674577728, 727501822004416, 4172725286118656 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..250

FORMULA

a(n) = (n+5)*hypergeom([-n-4, n], [2], -1) = Sum_{s=1..n+5} binomial(n+5,s) * binomial(s+n-2,n-1) for n >= 1. - Petros Hadjicostas, Feb 13 2021

MAPLE

T:= proc(i, j) option remember;

      if j=0 then 1

    elif i=0 then 0

    else add(add(T(h, m), m=0..j), h=0..i-1)

  fi; end:

seq(T(n+5, n), n=0..20); # G. C. Greubel, Jan 23 2020

MATHEMATICA

T[i_, j_]:= T[i, j]= If[j==0, 1, If[i==0, 0, Sum[T[h, m], {h, 0, i-1}, {m, 0, j}]]]; Table[T[n+5, n], {n, 0, 20}] (* G. C. Greubel, Jan 23 2020 *)

PROG

(Sage)

@CachedFunction

def T(i, j):

    if (j==0): return 1

    elif (i==0): return 0

    else: return sum(sum(T(h, m) for m in (0..j)) for h in (0..i-1))

[T(n+5, n) for n in (0..20)] # G. C. Greubel, Jan 23 2020

CROSSREFS

Cf. A055807, A055809, A055810, A055811, A055815, A055816.

Sequence in context: A251019 A251012 A092050 * A075934 A075939 A075935

Adjacent sequences:  A055814 A055815 A055816 * A055818 A055819 A055820

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 28 2000

STATUS

approved

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Last modified April 23 13:25 EDT 2021. Contains 343204 sequences. (Running on oeis4.)