A143551 G.f. satisfies: A(x) = 1 + x*A(x)^5*A(-x).

1, 1, 4, 29, 196, 1781, 14000, 139234, 1176340, 12283166, 108258380, 1165438808, 10561185568, 116096795195, 1072964739264, 11975785105572, 112313638368948, 1268177365551626, 12029082865935512, 137067430786661911

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Formula

G.f. satisfies: A(x) + A(-x) = 1 + [A(x)*A(-x)] + x^2*[A(x)*A(-x)]^6.

Example

G.f. A(x) = 1 + x + 4*x^2 + 29*x^3 + 196*x^4 + 1781*x^5 + 14000*x^6 +...
Related expansions:
A(x)^5 = 1 + 5*x + 30*x^2 + 235*x^3 + 1845*x^4 + 16576*x^5 + 144270*x^6 +...
A(x)*A(-x) = 1 + 7*x^2 + 350*x^4 + 25165*x^6 + 2121330*x^8 +...
[A(x)*A(-x)]^6 = 1 + 42*x^2 + 2835*x^4 + 231350*x^6 +...

Prog

(PARI) {a(n)=local(A=1+x*O(x^n)); for(i=0, n, A=1+x*A^5*subst(A, x, -x)); polcoeff(A, n)}

Crossrefs

Cf. A143550, A143552, A143553, A143554.

Sequence in context: A364404 A121191 A129587 * A288913 A100022 A001883

Adjacent sequences: A143548 A143549 A143550 * A143552 A143553 A143554

Keyword

nonn

Author

Paul D. Hanna, Aug 24 2008

Status

approved