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A256980 Irregular triangle read by rows: row n gives number of connected graphs on n nodes with forcing number k (n>=1, k>=0). 0
1, 1, 1, 1, 2, 4, 8, 11, 2, 35, 68, 9, 252, 524, 75, 2, 2994, 7161, 934, 28, 68665, 171684, 20296, 432, 3, 3013075, 7849829, 840786, 12766, 115 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

REFERENCES

C. E. Larson and N. Van Cleemput, Forcing Independence, Croatica Chemica Acta, Vol. 86, No. 4, Dec. 2013, 469-475.

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

Triangle begins:

1

1

1 1

2 4

8 11 2

35 68 9

252 524 75 2

2994 7161 934 28

68665 171684 20296 432 3

3013075 7849829 840786 12766 115

...

CROSSREFS

Sequence in context: A210108 A217131 A116636 * A014425 A028889 A235700

Adjacent sequences:  A256977 A256978 A256979 * A256981 A256982 A256983

KEYWORD

nonn,tabf,more

AUTHOR

N. J. A. Sloane, Apr 24 2015

STATUS

approved

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Last modified October 16 06:30 EDT 2019. Contains 328050 sequences. (Running on oeis4.)