A138209 G.f.: A(x) = 1 + x*(1 + x*(1 + x*(...(1 + x*(...)^(-3n) )...)^-9)^-6)^-3.

1, 1, -3, 24, -307, 5367, -118836, 3185098, -100249284, 3625011513, -148109085520, 6748573217802, -339316619619180, 18662532511884138, -1114624766173882896, 71841450181505629686, -4970296376217834343751, 367389368833834570991097

Offset

0,3

Links

Table of n, a(n) for n=0..17.

Example

G.f.: A(x)=1+x/B(x)^3, B(x)=1+x/C(x)^6, C(x)=1+x/D(x)^9, D(x)=1+x/E(x)^12, ...
where A(x),B(x),C(x),... are the g.f. of the sequences given below.
A=[1,1,-3,24,-307,5367,-118836,3185098,-100249284,...];
B=[1,1,-6,75,-1352,31167,-867294,28172631,-1044977994,...];
C=[1,1,-9,153,-3567,102591,-3461832,133195605,-5737614804,...];
D=[1,1,-12,258,-7384,254955,-10139508,452535442,-22298633472,...];
E=[1,1,-15,390,-13235,533700,-24472908,1245207030,-69239330640,...];
F=[1,1,-18,549,-21552,994392,-51685074,2955896076,-183324843810,...]; ...

Prog

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(j=0, n-1, A=1+x*A^(-3*(n-j))); polcoeff(A, n)}

Crossrefs

Cf. A121587, A138213, A138210, A138208.

Sequence in context: A365567 A258301 A365584 * A352235 A075142 A138428

Adjacent sequences: A138206 A138207 A138208 * A138210 A138211 A138212

Keyword

sign

Author

Paul D. Hanna, Mar 06 2008

Status

approved