0,4

G.f.: A(x)=1+x/B(x), 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,-1,4,-28,281,-3684,59731,-1154936,25950691,...];

B=[1,1,-3,21,-220,3015,-50721,1009311,-23180763,603647340,...];

C=[1,1,-5,50,-700,12250,-254086,6060285,-163013950,4877935870,...];

D=[1,1,-7,91,-1596,34062,-843003,23549442,-730039689,24824392005,...];

E=[1,1,-9,144,-3036,76527,-2204136,70735467,-2490112548,95152481622,...];

F=[1,1,-11,209,-5148,149721,-4923061,178674925,-7052351735,...]; ...

(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)}

Cf. A121587, A138211, A138210, A138209.

Sequence in context: A128318 A032274 A007559 this_sequence A071212 A090353 A076729

Adjacent sequences: A138205 A138206 A138207 this_sequence A138209 A138210 A138211

sign

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