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A123850 Triangle read by rows: T(n,k) = orientable embedding number gamma_k for bouquet B_n, n >= 0, 0 <= k <= [n/2]. 1
1, 1, 4, 2, 40, 80, 672, 3360, 1008, 16128, 161280, 185472 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 649.

LINKS

Table of n, a(n) for n=0..11.

FORMULA

Reference gives a recurrence.

EXAMPLE

Triangle begins:

1

1

4 2

40 80

672 3360 1008

16128 161280 185472

CROSSREFS

Columns give A005431, A123828. Row sums are (2n-1)1.

Sequence in context: A302890 A307974 A303625 * A280780 A264755 A120968

Adjacent sequences:  A123847 A123848 A123849 * A123851 A123852 A123853

KEYWORD

nonn,tabf,more

AUTHOR

N. J. A. Sloane, Nov 19 2006

STATUS

approved

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Last modified April 10 02:39 EDT 2020. Contains 333392 sequences. (Running on oeis4.)