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A193102
G.f.: exp( Sum_{n>=1} 2*sigma(n*3^n)*x^n/n ).
1
1, 8, 71, 478, 3248, 19674, 116885, 655064, 3602627, 19082622, 99353815, 503974610, 2518347829, 12341129010, 59691674707, 284343349874, 1339171125620, 6229010760982, 28686750790598, 130740792179088, 590661906472634, 2644740541614160
OFFSET
0,2
EXAMPLE
G.f.: A(x) = 1 + 8*x + 71*x^2 + 478*x^3 + 3248*x^4 + 19674*x^5 +...
log(A(x)) = 8*x + 78*x^2/2 + 242*x^3/3 + 1694*x^4/4 + 4368*x^5/5 + 19680*x^6/6 + 52480*x^7/7 +...+ 2*sigma(n*3^n)*x^n/n +...
PROG
(PARI) {a(n)=polcoeff(exp(sum(m=1, n, 2*sigma(m*3^m)*x^m/m)+x*O(x^n)), n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 15 2011
STATUS
approved