A007109 Number of labeled 2-regular oriented graphs with n nodes. (Formerly M5164)

1, 0, 0, 0, 0, 24, 570, 27900, 1827630, 152031600, 15453884376, 1884221030160, 271711899360000, 45788222207669040, 8922353083744943700, 1991728039234615305624, 505133808398958249480060

Offset

0,6

References

R. W. Robinson, personal communication.

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1982.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

R. W. Robinson, Table of n, a(n) for n = 0..48

Crossrefs

Sequence in context: A218726 A203487 A007110 * A158538 A171329 A077423

Adjacent sequences: A007106 A007107 A007108 * A007110 A007111 A007112

Keyword

nonn

Author

N. J. A. Sloane.

Status

approved