A110489 Row sums of a triangle based on the Catalan numbers.
1, 2, 5, 14, 43, 142, 497, 1828, 7037, 28326, 119361, 527748, 2454929, 12041410, 62354641, 340840118, 1963757863, 11896370734, 75549183725, 501393978466, 3467199478543, 24916100775758, 185646100106929, 1431332539961350
Offset: 0
Links
- G. C. Greubel, Table of n, a(n) for n = 0..595
Crossrefs
Cf. A110488.
Programs
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Mathematica
T[n_, 0] := CatalanNumber[n]; T[n_, 1] := CatalanNumber[n]; T[n_, n_] := 1; T[n_, k_] := Sum[2*(j + 1)*(k - 1)^j*Binomial[2 (n - k) + 1, n - k - j]/(n - k + j + 2), {j, 0, n - k}]; Table[Sum[T[n, k], {k, 0, n}], {n, 0, 50}] (* G. C. Greubel, Aug 29 2017 *)
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PARI
a(n) = sum(k=0, n, sum(j=0, (n-k), 2*(j+1)*(k-1)^j*binomial(2*(n-k)+1, n-k-j)/ (n-k+j+2))); \\ Michel Marcus, Aug 29 2017
Formula
a(n) = Sum_{k=0..n} Sum_{j=0..(n-k)} 2*(j+1)*(k-1)^j*C(2*(n-k)+1, n-k-j)/ (n-k+j+2).
Comments