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A121094 Isomers of polyenes attached to benzene (see Cyvin et al. for precise definition). 0
0, 1, 2, 2, 8, 9, 26, 28, 88, 89, 292, 297, 994, 1001, 3418, 3430, 11920, 11934, 41944, 41990, 149184, 149221, 534756, 534888, 1931394, 1931540, 7019976, 7020391, 25662396, 25662825, 94285650, 94287120, 347992480, 347993868 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..33.

B. N. Cyvin, E. Brendsdal, J. Brunvoll and S. J. Cyvin, Isomers of polyenes attached to benzene, Croatica Chemica Acta, 68 (1995), 63-73, M(x).

MAPLE

U0 := (1-sqrt(1-4*x))/2/x ;

V0 := 1+x*subs(x=x^2, U0) ;

Mb := ( subs(x=x^2, U0)^3 -subs(x=x^4, U0)*subs(x=x^2, V0) -subs(x=x^6, U0) +subs(x=x^6, V0) )/2 ; # (20)

Ma := ( subs(x=x^2, U0)^2*V0^2 -subs(x=x^3, V0)^2 -subs(x=x^4, U0)*subs(x=x^2, V0) +subs(x=x^6, V0) )/2 ; # (21)

M := Mb+Ma ;

taylor(%, x=0, 40) ;

gfun[seriestolist](%) ; # R. J. Mathar, Jul 26 2019

CROSSREFS

Sequence in context: A131659 A137726 A121098 * A029595 A320138 A325102

Adjacent sequences:  A121091 A121092 A121093 * A121095 A121096 A121097

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 11 2006

STATUS

approved

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Last modified January 17 18:00 EST 2020. Contains 330987 sequences. (Running on oeis4.)