login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A333476
Triangle read by rows: T(n,k) gives the number of ways to partition an n X k grid into rectangles of integer side lengths with 0 <= k <= n.
4
1, 1, 1, 1, 2, 8, 1, 4, 34, 322, 1, 8, 148, 3164, 70878, 1, 16, 650, 31484, 1613060, 84231996, 1, 32, 2864, 314662, 36911922, 4427635270, 535236230270, 1, 64, 12634, 3149674, 846280548, 233276449488, 64878517290010, 18100579400986674
OFFSET
0,5
LINKS
David A. Klarner and Spyros S. Magliveras, The number of tilings of a block with blocks, European Journal of Combinatorics 9 (1988), 317-330.
Joshua Smith and Helena Verrill, On dividing rectangles into rectangles
FORMULA
T(n,k) = A116694(n,k).
EXAMPLE
Triangle begins:
n\k| 0 1 2 3 4 5 6
---+--------------------------------------------------------
0| 1;
1| 1, 1;
2| 1, 2, 8;
3| 1, 4, 34, 322;
4| 1, 8, 148, 3164, 70878;
5| 1, 16, 650, 31484, 1613060, 84231996;
6| 1, 32, 2864, 314662, 36911922, 4427635270, 535236230270;
...
MAPLE
M:= proc(n) option remember; local k; k:= 2^(n-2);
`if`(n=1, Matrix([2]), Matrix(2*k, (i, j)->`if`(i<=k,
`if`(j<=k, M(n-1)[i, j], B(n-1)[i, j-k]),
`if`(j<=k, B(n-1)[i-k, j], 2*M(n-1)[i-k, j-k]))))
end:
B:= proc(n) option remember; local k; k:=2^(n-2);
`if`(n=1, Matrix([1]), Matrix(2*k, (i, j)->`if`(i<=k,
`if`(j<=k, B(n-1)[i, j], B(n-1)[i, j-k]),
`if`(j<=k, B(n-1)[i-k, j], M(n-1)[i-k, j-k]))))
end:
T:= proc(n, m) option remember; `if`((s-> 0 in s or s={1})(
{n, m}), 1, `if`(m>n, T(m, n), add(i, i=map(rhs,
[op(op(2, M(m)^(n-1)))]))))
end:
seq(seq(T(n, k), k=0..n), n=0..8); # Alois P. Heinz, Mar 23 2020
MATHEMATICA
M[n_] := M[n] = Module[{k = 2^(n - 2)}, If[n == 1, {{2}}, Table[If[i <= k, If[j <= k, M[n - 1][[i, j]], B[n - 1][[i, j - k]]], If[j <= k, B[n - 1][[i - k, j]], 2 M[n - 1][[i - k, j - k]]]], {i, 1, 2k}, {j, 1, 2k}]]];
B[n_] := B[n] = Module[{k = 2^(n - 2)}, If[n == 1, {{1}}, Table[If[i <= k, If[j <= k, B[n - 1][[i, j]], B[n - 1][[i, j - k]]], If[j <= k, B[n - 1][[i - k, j]], M[n - 1][[i - k, j - k]]]], {i, 1, 2k}, {j, 1, 2k}]]];
T[_, 0] = 1;
T[n_, k_] /; k > n := T[k, n];
T[n_, k_] := MatrixPower[M[k], n-1] // Flatten // Total;
Table[Table[T[n, k], {k, 0, n}], {n, 0, 8}] // Flatten (* Jean-François Alcover, Nov 23 2020, after Alois P. Heinz *)
CROSSREFS
Triangular version of A116694.
Main diagonal is given by A182275.
T(2n,n) gives A333495.
Sequence in context: A275980 A343918 A156029 * A120026 A329280 A109089
KEYWORD
nonn,tabl
AUTHOR
Peter Kagey, Mar 23 2020
STATUS
approved