OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
In Maple notation, a(n) = I^n*HermiteH(n, -3*I)
Recurrence: a(n) = 6*a(n-1) + 2*(n-1)*a(n-2). - Vaclav Kotesovec, Oct 13 2012
a(n) ~ 2^(n/2-1/2)*exp(-n/2+3*sqrt(2*n)-9/2)*n^(n/2)*(1+3*sqrt(2)/sqrt(n)). - Vaclav Kotesovec, Oct 13 2012
E.g.f.: exp(x^2+6*x). - Vaclav Kotesovec, Oct 21 2012
MAPLE
seq(expand(I^n*HermiteH(n, -I*3)), n=0..14);
MATHEMATICA
Table[I^n*HermiteH[n, -3I], {n, 0, 20}]
CoefficientList[Series[E^(x^2+6*x), {x, 0, 20}], x]*Range[0, 20]! (* Vaclav Kotesovec, Oct 21 2012 *)
PROG
(PARI) x='x+O('x^66); Vec(serlaplace(exp(x^2+6*x))) \\ Joerg Arndt, May 07 2013
(Magma) m:=50; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Exp(6*x + x^2))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 10 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Karol A. Penson, Jan 19 2003
EXTENSIONS
Edited and extended by Robert G. Wilson v, Jan 22 2003
STATUS
approved