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A011268 Triangle read by rows: number of P-graphs by number of edges and number of non-root nodes. 0
1, 1, 2, 1, 10, 3, 1, 30, 44, 4, 1, 70, 284, 134, 5, 1, 140, 1224, 1594, 329, 6, 1, 252, 4110, 11330, 6552, 700, 7, 1, 420, 11616, 58432, 71484, 21822, 1344, 8, 1, 660, 28908, 241098, 534562, 347274, 62370, 2388, 9, 1, 990, 65208, 842842, 3069360, 3612924 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

2,3

REFERENCES

R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. Math., 31 (1986), 47-63.

LINKS

Table of n, a(n) for n=2..52.

R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. Math., 31 (1986), 47-63.

FORMULA

Reference gives generating function.

CROSSREFS

Sequence in context: A144274 A144275 A247236 * A225911 A163235 A142963

Adjacent sequences:  A011265 A011266 A011267 * A011269 A011270 A011271

KEYWORD

tabl,nonn,easy,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 27 2004

STATUS

approved

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Last modified October 14 01:36 EDT 2019. Contains 327994 sequences. (Running on oeis4.)