A223143 G.f. satisfies: A(x)^3 = A(x^2)^3 + 9*x.

1, 3, -6, 27, -141, 819, -5022, 31968, -209202, 1398420, -9505854, 65499759, -456410943, 3210397173, -22763553876, 162524220984, -1167359075781, 8429107868541, -61148608627518, 445450238075655, -3257116365714831, 23896262127268719, -175854177039133998

Offset

0,2

Links

Paul D. Hanna, Table of n, a(n) for n = 0..300

Formula

G.f.: A(x) = ( 1 + Sum_{n>=0} 9*x^(2^n) )^(1/3).

Example

G.f.: A(x) = 1 + 3*x - 6*x^2 + 27*x^3 - 141*x^4 + 819*x^5 - 5022*x^6 +...
where
A(x)^3 = 1 + 9*x + 9*x^2 + 9*x^4 + 9*x^8 + 9*x^16 + 9*x^32 +...+ 9*x^(2^n) +...

Prog

(PARI) {a(n)=local(A=1+x); for(i=1, #binary(n), A=(subst(A, x, x^2)^3+9*x+x*O(x^n))^(1/3)); polcoeff(A, n, x)}
for(n=0, 30, print1(a(n), ", "))

Crossrefs

Cf. A223142, A107086, A223026.

Sequence in context: A215394 A222625 A060170 * A372039 A270889 A097678

Adjacent sequences: A223140 A223141 A223142 * A223144 A223145 A223146

Keyword

sign,changed

Author

Paul D. Hanna, Mar 15 2013

Status

approved