

A007139


Number of unlabeled bicolored bipartite graphs on 2n nodes having n nodes of each color with no edges between vertices of the same color and allowing the color classes to be interchanged.
(Formerly M4172)


12



1, 2, 6, 26, 192, 3014, 127757, 16853750, 7343780765, 10733574184956, 52867617324773592, 882178116079222400788, 50227997322550920824045262, 9837048598740665027344331562224, 6681839615514161556535851222043192179, 15867777966020615016665849049841756464001994
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OFFSET

0,2


REFERENCES

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1976.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


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KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



