A212421 Central coefficients of triangle A096815.

1, 1, 3, 6, 17, 42, 118, 320, 861, 2442, 6658, 18686, 52100, 146832, 410990, 1161722, 3282403, 9283968, 26336598, 74712158, 212613094, 605118528, 1726261816, 4926677982, 14079210098, 40247549662, 115175011608, 329707161766, 944566633454, 2707713181042

Offset

0,3

Links

Table of n, a(n) for n=0..29.

Formula

a(n) = T(2n,n), where T(n,k) = A096815(n,k).

Mathematica

T[n_, k_] := T[n, k] = If[n < k || k < 0, 0, If[k = 1 || k == n, 1, Sum[T[n-k, j]T[k, k-j], {j, 0, k}]]]
Table[T[2n, n], {n, 0, 50}]

Crossrefs

Cf. A096815, A096816, A212264, A212265, A212422

Sequence in context: A320807 A089264 A121399 * A238428 A363387 A232771

Adjacent sequences: A212418 A212419 A212420 * A212422 A212423 A212424

Keyword

nonn

Author

Emanuele Munarini, May 16 2012

Status

approved