A300865 Signed recurrence over binary enriched p-trees: a(n) = (-1)^(n-1) + Sum_{x + y = n, 0 < x <= y < n} a(x) * a(y).

1, 0, 1, 0, 1, 1, 2, 2, 4, 6, 10, 16, 27, 46, 77, 131, 224, 391, 672, 1180, 2050, 3626, 6344, 11276, 19863, 35479, 62828, 112685, 200462, 360627, 644199, 1162296, 2083572, 3768866, 6777314, 12289160, 22158106, 40255496, 72765144, 132453122, 239936528, 437445448

Offset

1,7

Links

Table of n, a(n) for n=1..42.

Mathematica

a[n_]:=a[n]=(-1)^(n-1)+Sum[a[k]*a[n-k], {k, 1, n/2}];
Array[a, 50]

Crossrefs

Cf. A000992, A001190, A007317, A063834, A099323, A196545, A220418, A273866, A273873, A289501, A290261, A300352, A300442, A300443, A300862, A300863, A300864, A300866.

Sequence in context: A270925 A331964 A084202 * A053637 A000016 A361223

Adjacent sequences: A300862 A300863 A300864 * A300866 A300867 A300868

Keyword

nonn

Author

Gus Wiseman, Mar 13 2018

Status

approved