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A179306
G.f.: A(x) = exp( Sum_{n>=1} A179307(n)*x^n/n ), where A179307(n) = Sum_{d|n} C(n,d)*sigma(d)*sigma(n/d).
1
1, 1, 5, 10, 40, 67, 262, 449, 1572, 2915, 8876, 16452, 51811, 93789, 271500, 518378, 1457658, 2734005, 7584475, 14282412, 38649578, 73773173, 193491639, 369696321, 971226618, 1845956358, 4730626121, 9114534520, 23083308650, 44287157822
OFFSET
0,3
EXAMPLE
G.f.: A(x) = 1 + x + 5*x^2 + 10*x^3 + 40*x^4 + 67*x^5 + 262*x^6 +...
log(A(x)) = x + 9*x^2/2 + 16*x^3/3 + 89*x^4/4 + 36*x^5/5 + 504*x^6/6 +...
PROG
(PARI) {a(n)=polcoeff(exp(sum(m=1, n, sumdiv(m, d, binomial(m, d)*sigma(d)*sigma(m/d))*x^m/m)+x*O(x^n)), n)}
CROSSREFS
Cf. A179307.
Sequence in context: A355327 A279764 A191580 * A117865 A249059 A163305
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 10 2010
STATUS
approved