A104443 Square of P(n,t) read by antidiagonals. P(n,t) = number of ways to split [t*n] into n arithmetic progressions each with t terms.

1, 1, 1, 1, 3, 1, 1, 2, 15, 1, 1, 2, 5, 105, 1, 1, 2, 4, 15, 945, 1, 1, 2, 4, 11, 55, 10395, 1, 1, 2, 4, 10, 23, 232, 135135, 1, 1, 2, 4, 10, 21, 68, 1161, 2027025, 1, 1, 2, 4, 10, 20, 59, 161, 6643, 34459425, 1, 1, 2, 4, 10, 20, 57, 125, 488, 44566, 654729075, 1

Offset

1,5

Links

Table of n, a(n) for n=1..66.

Example

Square array begins:
  1,        1,     1,    1,   1,   1,   1,   1,   1, ...
  1,        3,     2,    2,   2,   2,   2,   2,   2, ...
  1,       15,     5,    4,   4,   4,   4,   4,   4, ...
  1,      105,    15,   11,  10,  10,  10,  10,  10, ...
  1,      945,    55,   23,  21,  20,  20,  20,  20, ...
  1,    10395,   232,   68,  59,  57,  56,  56,  56, ...
  1,   135135,  1161,  161, 125, 119, 117, 116, 116, ...
  1,  2027025,  6643,  488, 349, 329, 323, 321, 320, ...
  1, 34459425, 44566, 1249, 848, 760, 745, 739, 737, ...
  ...

Crossrefs

Cf. A104429-A104442. P(1, _)=P(_, 1) = A000012, P(_, 2) = A001147.

Sequence in context: A328901 A362019 A016564 * A218489 A218332 A322506

Adjacent sequences: A104440 A104441 A104442 * A104444 A104445 A104446

Keyword

nonn,tabl

Author

Jonas Wallgren, Mar 17 2005

Extensions

More terms from Alois P. Heinz, Nov 18 2020

Status

approved