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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). 4
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 (list; graph; refs; listen; history; text; internal format)
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: A198834 A270925 A084202 * A053637 A000016 A060553

Adjacent sequences:  A300862 A300863 A300864 * A300866 A300867 A300868

KEYWORD

nonn

AUTHOR

Gus Wiseman, Mar 13 2018

STATUS

approved

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Last modified June 15 17:43 EDT 2019. Contains 324142 sequences. (Running on oeis4.)