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A187044 Row sums of number triangle A070895. 3
1, 2, 4, 9, 22, 59, 170, 525, 1716, 5917, 21362, 80533, 315516, 1281913, 5383622, 23330405, 104084736, 477371217, 2246811730, 10839493637, 53528916508, 270318789249, 1394426035918, 7341439399397, 39413238225512, 215607783811041 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..795

FORMULA

E.g.f.: exp(x+x^2/2)*(sqrt(pi/2)*ERF(x/sqrt(2)) + 1).

Conjecture: a(n) -2*a(n-1) +(2-n)*a(n-2) +(n-2)*a(n-3)=0. - R. J. Mathar, Sep 29 2012

a(n) ~ (sqrt(2)+sqrt(Pi))/2 * exp(sqrt(n)-n/2-1/4)*n^(n/2) * (1+7/(24*sqrt(n))). - Vaclav Kotesovec, Aug 15 2013

a(n) = A193361(n+2). - Vaclav Kotesovec, Feb 14 2014

MATHEMATICA

CoefficientList[Series[E^(x+x^2/2)*(Sqrt[Pi/2]*Erf[x/Sqrt[2]]+1), {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Aug 15 2013 *)

CROSSREFS

Sequence in context: A210726 A046917 A237770 * A193361 A294281 A293854

Adjacent sequences:  A187041 A187042 A187043 * A187045 A187046 A187047

KEYWORD

nonn,easy

AUTHOR

Paul Barry, Mar 02 2011

STATUS

approved

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Last modified June 15 17:43 EDT 2019. Contains 324142 sequences. (Running on oeis4.)