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A308337
Expansion of e.g.f. exp(-1 + Product_{k>=1} 1/(1 - x^k/k)).
2
1, 1, 4, 21, 146, 1210, 11894, 133000, 1677668, 23439684, 359651232, 6000427884, 108157599120, 2092493844480, 43240336406136, 950021322002904, 22108068716440272, 543048769028068944, 14037848562783308160, 380851191359082217488, 10818262594065294568416
OFFSET
0,3
FORMULA
a(0) = 1; a(n) = Sum_{k=1..n} binomial(n-1,k-1)*A007841(k)*a(n-k).
MATHEMATICA
nmax = 20; CoefficientList[Series[Exp[Product[1/(1 - x^k/k), {k, 1, nmax}] - 1], {x, 0, nmax}], x] Range[0, nmax]!
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, May 20 2019
STATUS
approved