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A074354 Coefficient of q^3 in nu(n), where nu(0)=1, nu(1)=b and, for n>=2, nu(n)=b*nu(n-1)+lambda*(1+q+q^2+...+q^(n-2))*nu(n-2) with (b,lambda)=(1,2). 5
0, 0, 0, 0, 0, 14, 64, 218, 692, 1982, 5496, 14562, 37692, 95142, 236032, 576074, 1387780, 3304078, 7787656, 18190386, 42151116, 96972534, 221651472, 503650970, 1138286740, 2559944414, 5731095704, 12776843138, 28374100572 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

Coefficient of q^0 is A001045(n+1).

LINKS

Table of n, a(n) for n=0..28.

M. Beattie, S. Dăscălescu and S. Raianu, Lifting of Nichols Algebras of Type B_2, arXiv:math/0204075 [math.QA], 2002.

FORMULA

Conjectures from Colin Barker, Nov 18 2017: (Start)

G.f.: 2*x^5*(1 + 2*x)*(7 - 10*x - 13*x^2 + 12*x^3 + 12*x^4) / ((1 + x)^4*(1 - 2*x)^4).

a(n) = 4*a(n-1) + 2*a(n-2) - 20*a(n-3) - a(n-4) + 40*a(n-5) + 8*a(n-6) - 32*a(n-7) - 16*a(n-8) for n>10.

(End)

EXAMPLE

The first 6 nu polynomials are nu(0)=1, nu(1)=1, nu(2)=3, nu(3)=5+2q, nu(4)=11+8q+6q^2, nu(5)=21+22q+20q^2+14q^3+4q^4, so the coefficients of q^1 are 0,0,0,0,0,14.

CROSSREFS

Coefficients of q^0, q^1 and q^2 are in A001045, A074352 and A074353. Related sequences with other values of b and lambda are in A074082-A074089, A074035-A074363.

Sequence in context: A050396 A069964 A275127 * A212743 A124892 A126401

Adjacent sequences:  A074351 A074352 A074353 * A074355 A074356 A074357

KEYWORD

nonn

AUTHOR

Y. Kelly Itakura (yitkr(AT)mta.ca), Aug 21 2002

EXTENSIONS

More terms from Benoit Cloitre, Jan 16 2003

Corrected by T. D. Noe, Oct 25 2006

STATUS

approved

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Last modified April 16 07:59 EDT 2021. Contains 343030 sequences. (Running on oeis4.)