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-François Alcover, Nov 18 2020, after Alois P. Heinz *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, May 01 2004
EXTENSIONS
More terms from Alois P. Heinz, Sep 29 2008
STATUS
approved