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A122648
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Expansion of e.g.f.: exp(x^2)*(exp(2*x)+1)/2.
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0
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1, 1, 4, 10, 44, 156, 752, 3256, 17040, 84496, 475712, 2611104, 15687872, 93376960, 594638592, 3786534784, 25412227328, 171474649344, 1206965027840, 8569374206464, 63003419470848, 468111364627456, 3582366347030528, 27733474149611520, 220255800262627328
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) ~ exp(sqrt(2*n)-n/2-1/2)*2^(n/2-3/2)*n^(n/2). - Vaclav Kotesovec, Jun 27 2013
Conjecture: D-finite with recurrence a(n) -2*a(n-1) +2*(-2*n+3)*a(n-2) +4*(n-2)*a(n-3) +4*(n-2)*(n-3)*a(n-4)=0. - R. J. Mathar, Aug 20 2021
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MATHEMATICA
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CoefficientList[Series[E^(x^2)*(E^(2*x)+1)/2, {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Jun 27 2013 *)
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PROG
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(PARI) my(x='x+O('x^30)); Vec(serlaplace(exp(x^2)*(exp(2*x)+1)/2))) \\ Michel Marcus, May 28 2019
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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