A187044 Row sums of number triangle A070895.

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

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

Cf. A070895, A193361.

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