A055826 a(n) = T(2n+2,n), array T as in A055818.

1, 11, 60, 328, 1800, 9924, 54964, 305680, 1706256, 9554620, 53653996, 302038488, 1703995800, 9631951476, 54539233380, 309296779296, 1756495236128, 9987721546860, 56857004161180, 324008331785320, 1848182861702184

Offset

0,2

Links

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

Maple

T:= proc(i, j) option remember;
      if i=0 or j=0 then 1
    else add(add(T(h, m), m=0..j), h=0..i-1)
  fi; end:
seq(T(n+2, n), n=0..30); # G. C. Greubel, Jan 22 2020

Mathematica

T[i_, j_]:= T[i, j]= If[i==0 || j==0, 1, Sum[T[h, m], {h, 0, i-1}, {m, 0, j}]]; Table[T[n+2, n], {n, 0, 25}] (* G. C. Greubel, Jan 22 2020 *)

Prog

(Sage)
@CachedFunction
def T(i, j):
    if (i==0 or j==0): return 1
    else: return sum(sum(T(h, m) for m in (0..j)) for h in (0..i-1))
[T(n+2, n) for n in (0..30)] # G. C. Greubel, Jan 22 2020

Crossrefs

Cf. A055818, A055819, A055820, A055821, A055822, A055823, A055824, A055825, A055827, A055828, A055829.

Sequence in context: A050483 A066999 A224291 * A324622 A156704 A248874

Adjacent sequences: A055823 A055824 A055825 * A055827 A055828 A055829

Keyword

nonn

Author

Clark Kimberling, May 28 2000

Status

approved