A185179 Irregular triangle, read by rows, of the A185178(n) values of the permanent of an n X n (0,1)-matrix (n>=3) with exactly three 1's in each row and each column.

6, 9, 12, 13, 17, 18, 20, 36, 24, 25, 26, 27, 30, 31, 32, 54, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 48, 49, 52, 72, 78, 81

Offset

3,1

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..36.

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).

Example

Triangle begins:
6
9
12, 13
17, 18, 20, 36
24, 25, 26, 27, 30, 31, 32, 54,
33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 48, 49, 52, 72, 78, 81

Crossrefs

Cf. A185178, A185177, A176211, A176212.

Sequence in context: A081392 A225868 A185177 * A072546 A344805 A295670

Adjacent sequences: A185176 A185177 A185178 * A185180 A185181 A185182

Keyword

nonn,tabf,hard,more

Author

Vladimir Shevelev, Feb 19 2011

Status

approved