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A144575
E,g.f.: exp(1-sqrt(1-2*x-3*x^2)).
1
1, 1, 5, 25, 217, 2321, 32221, 536425, 10547825, 238451617, 6103391221, 174418724921, 5506024371145, 190282381973425, 7145586497798477, 289733147423281801, 12615792602988127201, 587128127734854278465, 29084008051746449028325, 1527881758843209566647897
OFFSET
0,3
FORMULA
a(n) ~ 3^(n-1/2)*sqrt(2)*n^(n-1)/exp(n-1). - Vaclav Kotesovec, Jun 02 2013
Conjecture D-finite with recurrence: a(n) +(-2*n+3)*a(n-1) +(-3*n^2+12*n-10)*a(n-2) +3*(-2*n+3)*a(n-3) -9*(n-1)*(n-3)*a(n-4)=0. - R. J. Mathar, Jan 24 2020
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Exp[1-Sqrt[1-2x-3x^2]], {x, 0, nn}], x] Range[ 0, nn]!] (* Harvey P. Dale, Mar 26 2013 *)
CROSSREFS
Sequence in context: A080631 A080632 A245166 * A327619 A005452 A061839
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 07 2009
STATUS
approved