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A094089 E.g.f.: exp(-1)*Sum((1+2*x)^binomial(n,2)/n!, n=0..infinity). 1
1, 1, 5, 53, 873, 20457, 634541, 24950557, 1203940177, 69583310545, 4726132141013, 371490917377285, 33369568795430841, 3389380003596443833, 385790631214713169789, 48829461608868817380845, 6826282320001018166712481, 1047822371119145840154900897 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..150

MAPLE

A:= proc(k) exp(-1) *add((1+2*x)^binomial(n, 2)/ n!, n=0..k) end:

a:= proc(n) Digits:= 10+3*n; round(coeftayl(A(3*n+5), x=0, n)*n!) end:

seq(a(n), n=0..25);  # Alois P. Heinz, Sep 29 2008

MATHEMATICA

A[k_] := (1/E) Sum[(1 + 2x)^Binomial[n, 2]/n!, {n, 0, k}];

a[n_] := SeriesCoefficient[A[3n + 5], {x, 0, n}] n! // Round;

a /@ Range[0, 25] (* Jean-Fran├žois Alcover, Nov 18 2020, after Alois P. Heinz *)

CROSSREFS

Sequence in context: A118583 A090360 A123130 * A231866 A196659 A128943

Adjacent sequences:  A094086 A094087 A094088 * A094090 A094091 A094092

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, May 01 2004

EXTENSIONS

More terms from Alois P. Heinz, Sep 29 2008

STATUS

approved

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Last modified October 16 06:14 EDT 2021. Contains 348040 sequences. (Running on oeis4.)