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A055826
a(n) = T(2n+2,n), array T as in A055818.
8
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
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
KEYWORD
nonn
AUTHOR
Clark Kimberling, May 28 2000
STATUS
approved