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A036758 Number of edge-rooted tree-like octagonal systems. 1
1, 5, 31, 216, 1617, 12705, 103358, 863161, 7357277, 63747221, 559809997, 4971528380, 44572279612, 402883616972, 3667455453895, 33592221383213, 309375866119789, 2863158467711801, 26613026976466819, 248338952866938164 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

S. J. Cyvin et al., Enumeration of tree-like octagonal systems: catapolyoctagons, ACH Models in Chem. 134 (1997), 55-70.

LINKS

Table of n, a(n) for n=1..20.

J. Brunvoll et al., Enumeration of tree-like octagonal systems, J. Math. Chem., 21 (1997), 193-196.

FORMULA

G.f. G(x) = G satisfies G=x(1+5G+6G^2+G^3).

MAPLE

Order := 30: S := solve(series(G/(1+5*G+6*G^2+G^3), G)=x, G);

CROSSREFS

Sequence in context: A087457 A146962 A269730 * A153232 A287899 A110379

Adjacent sequences:  A036755 A036756 A036757 * A036759 A036760 A036761

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Emeric Deutsch, Feb 28 2004

STATUS

approved

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Last modified May 21 15:32 EDT 2019. Contains 323444 sequences. (Running on oeis4.)