A138211 G.f.: A(x) = 1 + x*(1 + x*(1 + x*(...(1 + x*(...)^(2n-1))...)^5)^3)^1.

1, 1, 1, 3, 18, 166, 2070, 32505, 614918, 13600671, 344202033, 9806468970, 310553772735, 10820519947581, 411338412455910, 16940944600551504, 751397442828052440, 35707884976794347170, 1810006747594245718317

Offset

0,4

Links

Table of n, a(n) for n=0..18.

Example

G.f.: A(x)=1+x*B(x)^1, B(x)=1+x*C(x)^3, C(x)=1+x*D(x)^5, D(x)=1+x*E(x)^7, ...
where A(x),B(x),C(x),... are the g.f. of the sequences given below.
A=[1,1,1,3,18,166,2070,32505,614918,13600671,...];
B=[1,1,3,18,166,2070,32505,614918,13600671,344202033,...];
C=[1,1,5,45,570,9175,177836,4016810,103426120,2987875840,...];
D=[1,1,7,84,1358,26957,626871,16609768,492427321,16126773012,...];
E=[1,1,9,135,2658,62892,1712034,52281819,1762364970,64849739238,...];
F=[1,1,11,198,4598,126456,3950837,136929254,5186142291,212476739640,...];

Prog

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(j=0, n-1, A=1+x*A^(2*(n-j)-1)); polcoeff(A, n)}

Crossrefs

Cf. A095793, A138212, A138213, A138214, A138215, A138216.

Sequence in context: A319938 A377074 A053513 * A052668 A224788 A121423

Adjacent sequences: A138208 A138209 A138210 * A138212 A138213 A138214

Keyword

nonn

Author

Paul D. Hanna, Mar 06 2008

Status

approved