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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
OFFSET
0,3
LINKS
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-François Alcover, Nov 18 2020, after Alois P. Heinz *)
CROSSREFS
Sequence in context: A090360 A367156 A123130 * A357343 A377323 A231866
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, May 01 2004
EXTENSIONS
More terms from Alois P. Heinz, Sep 29 2008
STATUS
approved