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A291632
Column 1 of A122832.
1
0, 1, 2, 9, 28, 125, 486, 2317, 10424, 53433, 267850, 1470161, 8032212, 46925749, 275437358, 1702883925, 10630404976, 69192858737, 455957606034, 3110617216153, 21512638153100, 153234193139181, 1107087138215542, 8206182165264029, 61703155328534568
OFFSET
0,3
FORMULA
E.g.f.: x*exp(x*(x+1)).
Recurrence: (n-1)*a(n) = n*a(n-1) + 2*(n-1)*n*a(n-2).
a(n) ~ 2^(n/2 - 1) * n^((n+1)/2) * exp(sqrt(n/2) - n/2 - 1/8).
MATHEMATICA
Table[n!*Sum[Binomial[i, n - 1 - i]/i!, {i, 0, n - 1}], {n, 0, 30}]
CoefficientList[Series[x*E^(x*(x+1)), {x, 0, 20}], x] * Range[0, 20]!
CROSSREFS
Sequence in context: A307400 A323682 A086511 * A328281 A324372 A138912
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Aug 28 2017
STATUS
approved