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A097713
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Column 1 of triangle A097712.
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2
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1, 3, 8, 25, 111, 809, 10360, 236952, 9708797, 714862984, 95000655195, 22902964060238, 10070812803900694, 8120691251242651341, 12070960239863869828931, 33238610095183531376362138
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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MATHEMATICA
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T[n_, k_]:= T[n, k]= If[n<0 || k>n, 0, If[k==0 || k==n, 1, T[n-1, k] + Sum[T[n-1, j]*T[j, k-1], {j, 0, n-1}] ]]; (* T=A097712 *)
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PROG
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(SageMath)
@CachedFunction
if k<0 or k>n: return 0
elif k==0 or k==n: return 1
else: return T(n-1, k) + sum(T(n-1, j)*T(j, k-1) for j in range(n))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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