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 A300864 Signed recurrence over strict trees: a(n) = -1 + Sum_{y1 + ... + yk = n, y1 > ... > yk > 0, k > 1} a(y1) * ... * a(yk). 4
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,7 LINKS 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

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Last modified January 19 10:37 EST 2021. Contains 340269 sequences. (Running on oeis4.)