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A121095 Isomers of polyenes attached to benzene (see Cyvin et al. for precise definition). 0
0, 0, 1, 4, 14, 47, 164, 565, 1982, 6977, 24850, 89082, 321855, 1169853, 4276923, 15713799, 57998270, 214934984, 799473752, 2983682702, 11169374372, 41929478873, 157807392886, 595340271682, 2250901007539, 8527699269192, 32369066434276 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..26.

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

MAPLE

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

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

C := ( subs(x=x^2, U0)^3 -3*subs(x=x^4, U0)*subs(x=x^2, V0) -subs(x=x^6, U0) +3*subs(x=x^6, V0) )/6 ; # (19)

taylor(%, x=0, 60) ;

L := gfun[seriestolist](%) ;

seq(op(2*i+1, L), i=1..(nops(L)-1)/2) ; # R. J. Mathar, Jul 26 2019

CROSSREFS

Sequence in context: A137284 A228178 A000908 * A264816 A015651 A022632

Adjacent sequences:  A121092 A121093 A121094 * A121096 A121097 A121098

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 11 2006

STATUS

approved

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Last modified January 23 04:16 EST 2020. Contains 331168 sequences. (Running on oeis4.)