A135078 E.g.f. A(x) = 1 + Sum_{n>=1} (1/n!)*Product_{k=0..n-1} [exp(3^k*x) - 1].
1, 1, 4, 46, 1519, 145795, 41134753, 34354750885, 85260288495316, 630102185300832652, 13884412839047621240875, 912975607895806507921828357, 179255108346123463104458490745825
Offset: 0
Keywords
Examples
A(x) = 1 + x + 4x^2/2! + 46x^3/3! + 1519x^4/4! + 145795x^5/5! +...; A(x) = 1 + [exp(x)-1] + [exp(x)-1][exp(3x)-1]/2! + [exp(x)-1][exp(3x)-1][exp(9x)-1]/3! + [exp(x)-1][exp(3x)-1][exp(9x)-1][exp(27x)-1]/4! +...
Programs
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PARI
{a(n)=n!*polcoeff(1+sum(j=1,n,(1/j!)*prod(k=0,j-1,1*exp(3^k*x)-1)),n)}