A259985 Triangle read by rows: coefficients of rook polynomials.

1, 1, 1, 1, 4, 2, 1, 9, 18, 6, 1, 16, 72, 96, 24, 1, 20, 130, 320, 265, 44, 1, 24, 204, 752, 1185, 672, 80, 1, 28, 294, 1456, 3521, 3892, 1617, 144, 1, 32, 400, 2496, 8264, 14272, 11776, 3776, 264, 1, 36, 522, 3936, 16659, 39924, 52071, 33480, 8577, 484, 1, 40, 660, 5840, 30210, 93568, 171060, 175360, 90745, 19080, 888, 1, 44, 814, 8272, 50677, 193556, 461208, 667832, 554532, 236808, 41745, 1632

Offset

0,5

Links

Table of n, a(n) for n=0..77.

Earl Glen Whitehead, Jr., Four-discordant permutations, J. Austral. Math. Soc. Ser. A 28 (1979), no. 3, 369-377.

Earl Glen Whitehead, Jr., Four-discordant permutations (Table 1) (Annotated scanned table)

Example

Triangle begins:
1;
1,  1;
1,  4,  2;
1,  9,  18,    6;
1, 16,  72,   96,    24;
1, 20, 130,  320,   265,    44;
1, 24, 204,  752,  1185,   672,     80;
1, 28, 294, 1456,  3521,  3892,   1617,    144;
1, 32, 400, 2496,  8264, 14272,  11776,   3776,   264;
1, 36, 522, 3936, 16659, 39924,  52071,  33480,  8577,   484;
1, 40, 660, 5840, 30210, 93568, 171060, 175360, 90745, 19080, 888; ...

Crossrefs

Diagonals give A004306, A005777, A005778.

Sequence in context: A338397 A063983 A367178 * A144084 A021010 A342088

Adjacent sequences: A259982 A259983 A259984 * A259986 A259987 A259988

Keyword

nonn,tabl

Author

N. J. A. Sloane, Jul 13 2015

Status

approved