OFFSET
0,3
FORMULA
a(0) = 1; a(n) = Sum_{k=1..n} (2*k - 1)*binomial(n-1,k-1)*a(n-k).
MATHEMATICA
nmax = 23; CoefficientList[Series[Exp[1 - Exp[x] (1 - 2 x)], {x, 0, nmax}], x] Range[0, nmax]!
a[n_] := a[n] = Sum[(2 k - 1) Binomial[n - 1, k - 1] a[n - k], {k, 1, n}]; a[0] = 1; Table[a[n], {n, 0, 23}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, May 09 2019
STATUS
approved