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A138211 G.f.: A(x) = 1 + x*(1 + x*(1 + x*(...(1 + x*(...)^(2n-1))...)^5)^3)^1. 7

%I #2 Mar 30 2012 18:37:09

%S 1,1,1,3,18,166,2070,32505,614918,13600671,344202033,9806468970,

%T 310553772735,10820519947581,411338412455910,16940944600551504,

%U 751397442828052440,35707884976794347170,1810006747594245718317

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

%e 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, ...

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

%e A=[1,1,1,3,18,166,2070,32505,614918,13600671,...];

%e B=[1,1,3,18,166,2070,32505,614918,13600671,344202033,...];

%e C=[1,1,5,45,570,9175,177836,4016810,103426120,2987875840,...];

%e D=[1,1,7,84,1358,26957,626871,16609768,492427321,16126773012,...];

%e E=[1,1,9,135,2658,62892,1712034,52281819,1762364970,64849739238,...];

%e F=[1,1,11,198,4598,126456,3950837,136929254,5186142291,212476739640,...];

%o (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)}

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

%K nonn

%O 0,4

%A _Paul D. Hanna_, Mar 06 2008

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Last modified April 23 12:08 EDT 2024. Contains 371912 sequences. (Running on oeis4.)