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A305572 a(n) = (-1)^(n-1) + Sum_{d|n, d>1} a(n/d)^d. 0
1, 0, 2, 0, 2, 4, 2, 0, 10, 4, 2, 32, 2, 4, 42, 0, 2, 228, 2, 32, 138, 4, 2, 1536, 34, 4, 1514, 32, 2, 3940, 2, 0, 2058, 4, 162, 102944, 2, 4, 8202, 1536, 2, 51940, 2, 32, 207370, 4, 2, 3538944, 130, 3204, 131082, 32, 2, 15668836, 2082, 1536, 524298, 4, 2, 54327840 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..60.

FORMULA

a(n) = Sum_t (-1)^(n-k) where the sum is over all same-trees of weight n (see A281145 for definition) and k is the number of leaves.

MATHEMATICA

a[n_]:=a[n]=(-1)^(n-1)+Sum[a[n/y]^y, {y, Divisors[n]//Rest}];

Array[a, 40]

CROSSREFS

Cf. A196545, A273873, A281145, A289078, A289079, A289501, A290261, A290971, A291441, A300862-A300866.

Sequence in context: A015910 A182256 A164993 * A223487 A226911 A291956

Adjacent sequences:  A305569 A305570 A305571 * A305573 A305574 A305575

KEYWORD

nonn

AUTHOR

Gus Wiseman, Jun 05 2018

STATUS

approved

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Last modified September 27 03:21 EDT 2020. Contains 337380 sequences. (Running on oeis4.)