A300864 Signed recurrence over strict trees: a(n) = -1 + Sum_{y1 + ... + yk = n, y1 > ... > yk > 0, k > 1} a(y1) * ... * a(yk).

1, 1, 0, 1, 0, 0, 2, -1, 0, 4, -6, 6, 6, -24, 38, -17, -64, 188, -230, -6, 662, -1432, 1286, 1210, -6362, 10692, -5530, -18274, 57022, -74364, 174, 216703, -489544, 467860, 391258, -2256430, 3948206, -2234064, -6725362, 21920402, -29716570, 2095564, 84595798, -198418242, 197499846

Offset

1,7

Links

Table of n, a(n) for n=1..45.

Mathematica

a[n_]:=a[n]=-1+Sum[Times@@a/@y, {y, Select[IntegerPartitions[n], Length[#]>1&&UnsameQ@@#&]}];
-Array[a, 40]

Crossrefs

Cf. A000992, A018819, A063834, A099323, A196545, A220418, A273866, A273873, A289501, A290261, A300862, A300863, A300865, A300866.

Sequence in context: A247268 A266867 A151852 * A300184 A160168 A077929

Adjacent sequences: A300861 A300862 A300863 * A300865 A300866 A300867

Keyword

sign

Author

Gus Wiseman, Mar 13 2018

Status

approved