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A192497 G.f. satisfies: A(x) = 1 + Sum_{n>=1} x^n*A(x)^sigma(n), where sigma(n) = A000203(n) is the sum of divisors of n. 0
1, 1, 2, 6, 20, 73, 281, 1124, 4633, 19547, 84023, 366695, 1620513, 7237034, 32609389, 148066067, 676805101, 3111807931, 14381741533, 66775448718, 311332294182, 1456999560630, 6841841485578, 32228152992893, 152241706312812, 721055062770213 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..25.

EXAMPLE

G.f.: A(x) = 1 + x + 2*x^2 + 6*x^3 + 20*x^4 + 73*x^5 + 281*x^6 +...

The g.f. satisfies:

A(x) = 1 + x*A(x) + x^2*A(x)^3 + x^3*A(x)^4 + x^4*A(x)^7 + x^5*A(x)^6 + x^6*A(x)^12 + x^7*A(x)^8 + x^8*A(x)^15 +...

PROG

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

CROSSREFS

Sequence in context: A150140 A061396 A230823 * A104632 A194956 A150141

Adjacent sequences:  A192494 A192495 A192496 * A192498 A192499 A192500

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jul 02 2011

STATUS

approved

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Last modified August 3 05:55 EDT 2020. Contains 336197 sequences. (Running on oeis4.)