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A179468 G.f. satisfies: A(x) = exp( Sum_{n>=1} A(sigma(n)*x^n)*x^n/n ). 0
1, 1, 2, 4, 10, 22, 62, 146, 420, 1050, 3124, 7956, 23957, 62486, 192129, 509457, 1560782, 4196095, 13066095, 35437076, 109838408, 301261013, 944939968, 2605796828, 8124857765, 22597326279, 71095025143, 198583977503 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..27.

EXAMPLE

G.f.: A(x) = 1 + x + 2*x^2 + 4*x^3 + 10*x^4 + 22*x^5 + 62*x^6 +...

log(A(x)) = A(x)*x + A(3*x^2)*x^2/2 + A(4*x^3)*x^3/3 + A(7*x^4)*x^4/4 +...

CROSSREFS

{a(n)=local(A=1+x), for(i=1, n, A=exp(sum(m=1, n, subst(A, x, sigma(m)*x^m+x*O(x^n))*x^m/m))), polcoeff(A, n)}

Sequence in context: A148086 A005962 A208062 * A203254 A076875 A179490

Adjacent sequences:  A179465 A179466 A179467 * A179469 A179470 A179471

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jul 15 2010

STATUS

approved

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Last modified October 19 15:34 EDT 2021. Contains 348091 sequences. (Running on oeis4.)