0,3

G.f.: A(x)=1+x*B(x)^4, B(x)=1+x*C(x)^8, C(x)=1+x*D(x)^12, D(x)=1+x*E(x)^16,...

where A(x),B(x),C(x),... are the g.f. of the sequences given below.

A=[1,1,4,38,596,13137,373544,13008184,535947320,25492727304,...];

B=[1,1,8,124,2792,81462,2902528,121830916,5880235184,...];

C=[1,1,12,258,7612,278991,12084552,600710380,33615167976,...];

D=[1,1,16,440,16080,711740,36459968,2105685752,134824193120,...];

E=[1,1,20,670,29220,1517725,89938984,5933795760,429195194520,...];

F=[1,1,24,948,48056,2866962,193128768,14351122716,1159330814736,...]; ...

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(j=0, n-1, A=1+x*A^(4*(n-j))); polcoeff(A, n)}

Cf. A095793, A138211, A138212, A138213, A138215, A138216.

Sequence in context: A120974 A113664 A077745 this_sequence A138562 A096332 A084284

Adjacent sequences: A138211 A138212 A138213 this_sequence A138215 A138216 A138217

nonn

Paul D. Hanna (pauldhanna(AT)juno.com), Mar 06 2008