A185178 Number of different values of the permanent of an n X n (0,1)-matrix with exactly three 1's in each row and each column.

1, 1, 2, 4, 8, 18

Offset

3,3

Comments

The values a(n) are unknown for n>=9.

References

V. I. Bolshakov, On spectrum of permanent on Lambda_n^k, Proc. of Seminar on Discrete Math. and Appl., Moscow State Univ. (1986), 65-73 (in Russian).

Links

Table of n, a(n) for n=3..8.

V. S. Shevelev, Some problems of the theory of enumerating the permutations with restricted position, Journal of Soviet Mathematics, 61 (4) (1992) 2272-2317 (see pp. 2307-2309).

Crossrefs

Cf. A185177 (values of the permanent), A176211, A176212.

Sequence in context: A372543 A255999 A171719 * A351471 A229718 A246469

Adjacent sequences: A185175 A185176 A185177 * A185179 A185180 A185181

Keyword

nonn,bref,hard,more

Author

Vladimir Shevelev, Feb 19 2011

Status

approved