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A332239
a(n) = n^(n-2) - Sum_{k=1..n-1} k^(k-2) * a(n-k).
1
1, 0, 2, 11, 96, 1058, 14292, 229273, 4268583, 90599501, 2161197285, 57273924968, 1670125069883, 53158796477452, 1834276943996477, 68212851126889959, 2719975462998554200, 115777392670653923870, 5240030485305934701421, 251291379101960875175412
OFFSET
1,3
FORMULA
G.f.: 1 - 1 / (1 + Sum_{k>=1} k^(k-2) * x^k).
MATHEMATICA
a[n_] := a[n] = n^(n - 2) - Sum[k^(k - 2) a[n - k], {k, 1, n - 1}]; Table[a[n], {n, 1, 20}]
nmax = 20; CoefficientList[Series[1 - 1/(1 + Sum[k^(k - 2) x^k, {k, 1, nmax}]), {x, 0, nmax}], x] // Rest
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 07 2020
STATUS
approved