A181196 T(n,k) = number of n X k matrices containing a permutation of 1..n*k in increasing order rowwise, columnwise, diagonally and (downwards) antidiagonally.
1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 5, 4, 1, 1, 1, 14, 29, 8, 1, 1, 1, 42, 290, 169, 16, 1, 1, 1, 132, 3532, 6392, 985, 32, 1, 1, 1, 429, 49100, 352184, 141696, 5741, 64, 1, 1, 1, 1430, 750325, 25097600, 36372976, 3142704, 33461, 128, 1, 1, 1, 4862, 12310294
Offset: 1
Examples
All solutions for 3 X 4: ..1..2..3..4....1..2..3..4....1..2..3..4....1..2..3..4....1..2..3..4 ..5..6..7..8....5..6..7..9....5..6..7.10....5..6..8..9....5..6..8.10 ..9.10.11.12....8.10.11.12....8..9.11.12....7.10.11.12....7..9.11.12 ... ..1..2..3..6....1..2..3..6....1..2..3..6....1..2..3..6....1..2..3..6 ..4..5..7..8....4..5..7..9....4..5..7.10....4..5..8..9....4..5..8.10 ..9.10.11.12....8.10.11.12....8..9.11.12....7.10.11.12....7..9.11.12 ... ..1..2..4..6....1..2..4..6....1..2..4..6....1..2..4..6....1..2..4..6 ..3..5..7..8....3..5..7..9....3..5..7.10....3..5..8..9....3..5..8.10 ..9.10.11.12....8.10.11.12....8..9.11.12....7.10.11.12....7..9.11.12 ... ..1..2..3..5....1..2..3..5....1..2..3..5....1..2..3..5....1..2..3..5 ..4..6..7..8....4..6..7..9....4..6..7.10....4..6..8..9....4..6..8.10 ..9.10.11.12....8.10.11.12....8..9.11.12....7.10.11.12....7..9.11.12 ... ..1..2..4..5....1..2..4..5....1..2..4..5....1..2..4..5....1..2..4..5 ..3..6..7..8....3..6..7..9....3..6..7.10....3..6..8..9....3..6..8.10 ..9.10.11.12....8.10.11.12....8..9.11.12....7.10.11.12....7..9.11.12 ... ..1..2..3..7....1..2..3..7....1..2..4..7....1..2..4..7 ..4..5..8..9....4..5..8.10....3..5..8..9....3..5..8.10 ..6.10.11.12....6..9.11.12....6.10.11.12....6..9.11.12
Links
- R. H. Hardin and Alois P. Heinz, Antidiagonals n = 1..30, flattened
- Brian T. Chan, Periodic P-Partitions, arXiv:1803.05594 [math.CO], 2018-2020.
- Ping Sun, Enumeration of standard Young tableaux of shifted strips with constant width, El. J. Comb., 24 (2017), #P2.41; arXiv:1506.07256 [math.CO], 2015.
- Antonio Vera López, Luis Martínez, Antonio Vera Pérez, Beatriz Vera Pérez and Olga Basova, Combinatorics related to Higman's conjecture I: Parallelogramic digraphs and dispositions, Linear Algebra and its Applications, Volume 530, 1 October 2017, p. 414-444. See Table 1.
Crossrefs
Programs
-
Maple
b:= proc(l) option remember; local n; n:= nops(l); `if`({l[]}={0}, 1, add(`if`((i=1 or l[i-1]<=l[i]) and l[i]> `if`(i=n, 0, l[i+1]), b(subsop(i=l[i]-1, l)), 0), i=1..n)) end: T:= (n,k)-> b([n$k]): seq(seq(T(n, 1+d-n), n=1..d), d=1..12); # Alois P. Heinz, Jul 24 2012
-
Mathematica
b[l_List] := b[l] = With[{n = Length[l]}, If[Union[l] == {0}, 1, Sum[If[(i == 1 || l[[i-1]] <= l[[i]]) && l[[i]] > If[i == n, 0, l[[i+1]]], b[ReplacePart[l, i -> l[[i]]-1]], 0], {i, 1, n}]]]; T[n_, k_] := b[Array[n&, k]]; Table[Table[T[n, 1+d-n], {n, 1, d}], {d, 1, 12}] // Flatten (* Jean-François Alcover, Mar 06 2015, after Alois P. Heinz *)
Formula
Empirical column 1: a(n) = a(n-1).
Empirical column 2: a(n) = a(n-1).
Empirical column 3: a(n) = 2*a(n-1).
Empirical column 4: a(n) = 6*a(n-1)-a(n-2).
Empirical column 5: a(n) = 24*a(n-1)-40*a(n-2)-8*a(n-3).
Empirical column 6: a(n) = 120*a(n-1)-1672*a(n-2)+544*a(n-3)-6672*a(n-4) +256*a(n-5).
Empirical column 7: a(n) = 720*a(n-1) -84448*a(n-2) +1503360*a(n-3) -17912224*a(n-4) -318223104*a(n-5) +564996096*a(n-6) +270471168*a(n-7) -11373824*a(n-8) +65536*a(n-9).
Comments