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A051946 G.f.: (1+4*x)/(1-x)^7. +0
5
1, 11, 56, 196, 546, 1302, 2772, 5412, 9867, 17017, 28028, 44408, 68068, 101388, 147288, 209304, 291669, 399399, 538384, 715484, 938630, 1216930, 1560780, 1981980, 2493855, 3111381, 3851316, 4732336, 5775176, 7002776, 8440432 (list; graph; listen)
OFFSET

0,2

COMMENT

Kekule numbers for certain benzenoids. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 18 2005

Equals row sums of triangle A143130, & binomial transform of {1, 10, 35, 60, 55, 26, 5, 0, 0, 0,...]. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jul 27 2008

REFERENCES

A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.

S. J. Cyvin and I. Gutman, Kekule structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p.233, # 5).

LINKS

Index entries for sequences related to linear recurrences with constant coefficients

FORMULA

a(n)=C(n+5, 5)*(5n+6)/6.

a(n)=(n+1)(n+2)(n+3)(n+4)(n+5)(5n+6)/720 - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 18 2005

a(n)=A034264(n+1). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 14 2008]

MAPLE

a:=n->(n+1)*(n+2)*(n+3)*(n+4)*(n+5)*(5*n+6)/720: seq(a(n), n=0..35); (Deutsch)

CROSSREFS

Partial sums of A027800.

Cf. A093562 ((5, 1) Pascal, column m=6).

Cf. A143130.

Sequence in context: A042503 A079547 A034264 this_sequence A114030 A071984 A101094

Adjacent sequences: A051943 A051944 A051945 this_sequence A051947 A051948 A051949

KEYWORD

easy,nonn

AUTHOR

Barry E. Williams, Dec 20 1999

EXTENSIONS

Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 18 2005

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


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