cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-6 of 6 results.

A275062 Number A(n,k) of permutations p of [n] such that p(i)-i is a multiple of k for all i in [n]; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 6, 1, 1, 1, 1, 2, 24, 1, 1, 1, 1, 1, 4, 120, 1, 1, 1, 1, 1, 2, 12, 720, 1, 1, 1, 1, 1, 1, 4, 36, 5040, 1, 1, 1, 1, 1, 1, 2, 8, 144, 40320, 1, 1, 1, 1, 1, 1, 1, 4, 24, 576, 362880, 1, 1, 1, 1, 1, 1, 1, 2, 8, 72, 2880, 3628800, 1
Offset: 0

Views

Author

Alois P. Heinz, Jul 15 2016

Keywords

Examples

			A(5,0) = A(5,5) = 1: 12345.
A(5,1) = 5! = 120: all permutations of {1,2,3,4,5}.
A(5,2) = 12: 12345, 12543, 14325, 14523, 32145, 32541, 34125, 34521, 52143, 52341, 54123, 54321.
A(5,3) = 4: 12345, 15342, 42315, 45312.
A(5,4) = 2: 12345, 52341.
A(7,4) = 8: 1234567, 1274563, 1634527, 1674523, 5234167, 5274163, 5634127, 5674123.
Square array A(n,k) begins:
  1,       1,     1,   1,   1,  1,  1, 1, 1, 1, 1, ...
  1,       1,     1,   1,   1,  1,  1, 1, 1, 1, 1, ...
  1,       2,     1,   1,   1,  1,  1, 1, 1, 1, 1, ...
  1,       6,     2,   1,   1,  1,  1, 1, 1, 1, 1, ...
  1,      24,     4,   2,   1,  1,  1, 1, 1, 1, 1, ...
  1,     120,    12,   4,   2,  1,  1, 1, 1, 1, 1, ...
  1,     720,    36,   8,   4,  2,  1, 1, 1, 1, 1, ...
  1,    5040,   144,  24,   8,  4,  2, 1, 1, 1, 1, ...
  1,   40320,   576,  72,  16,  8,  4, 2, 1, 1, 1, ...
  1,  362880,  2880, 216,  48, 16,  8, 4, 2, 1, 1, ...
  1, 3628800, 14400, 864, 144, 32, 16, 8, 4, 2, 1, ...
		

Crossrefs

A(k*n,n) for k=1..4 give: A000012, A000079, A000400, A009968.
Cf. A225816.

Programs

  • Maple
    A:= (n, k)-> mul(floor((n+i)/k)!, i=0..k-1):
    seq(seq(A(n, d-n), n=0..d), d=0..14);
  • Mathematica
    A[n_, k_] := Product[Floor[(n+i)/k]!, {i, 0, k-1}];
    Table[A[n, d-n], {d, 0, 14}, {n, 0, d}] // Flatten (* Jean-François Alcover, May 26 2019, from Maple *)

Formula

A(n,k) = Product_{i=0..k-1} floor((n+i)/k)!.
A(k*n,k) = (n!)^k = A225816(k,n).
For k > 0, A(n, k) ~ (2*Pi*n)^((k - 1)/2) * n! / k^(n + k/2). - Vaclav Kotesovec, Oct 02 2018

A264692 T(n,k)=Number of nXk arrays of permutations of 0..n*k-1 with rows nondecreasing modulo 3 and columns nondecreasing modulo 5.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 7, 6, 1, 4, 56, 80, 23, 1, 8, 348, 3196, 2051, 84, 2, 24, 4672, 171962, 465584, 59845, 897, 4, 72, 93864, 17647792, 207022624, 110630784, 3406328, 9292, 8, 216, 1776576, 2685878592
Offset: 1

Views

Author

R. H. Hardin, Nov 21 2015

Keywords

Comments

Table starts
.1....1.......1.........2.........4........8.........24......72.216
.1....1.......7........56.......348.....4672......93864.1776576
.1....6......80......3196....171962.17647792.2685878592
.1...23....2051....465584.207022624
.1...84...59845.110630784
.2..897.3406328
.4.9292

Examples

			Some solutions for n=3 k=4
..6..0.10..5....0.10..1.11....0..3..1.10...10..2..5.11....0..7.10.11
..3..1.11..2....6..5..8..2....6..9.11..5....0..4..1..7....6..3..5..2
..9..7..4..8....3..9..4..7....7..4..2..8....3..9..6..8....9..4..1..8
		

Crossrefs

Column 1 is A264656.
Row 1 is A264557.

A264698 T(n,k)=Number of nXk arrays of permutations of 0..n*k-1 with rows nondecreasing modulo 4 and columns nondecreasing modulo 5.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 3, 1, 2, 28, 68, 22, 1, 4, 159, 1541, 1378, 93, 2, 8, 1383, 37595, 102573, 26662, 790, 4, 16, 16818, 1947196, 20144706, 15357579, 975419, 7202, 8, 48, 168974, 148906136
Offset: 1

Views

Author

R. H. Hardin, Nov 21 2015

Keywords

Comments

Table starts
.1....1......1........1........2.......4.........8.....16.48
.1....2......5.......28......159....1383.....16818.168974
.1....3.....68.....1541....37595.1947196.148906136
.1...22...1378...102573.20144706
.1...93..26662.15357579
.2..790.975419
.4.7202

Examples

			Some solutions for n=4 k=4
.10.15.11..7....5..6.10.15....1.10..2..6....1..5.10..6....0..5.15.11
..5.13..1..2....0.13.11..7....3.15..7.11...13.15..7.11...12..6.10..2
..0..9..6..3...12..9..1..3....8..0.12.14....4..0..8.12....4..8..1.13
.12..4..8.14....8..4..2.14....4..5.13..9....9..2.14..3....9.14..7..3
		

Crossrefs

Column 1 is A264656.
Row 1 is A264635.

A264714 T(n,k)=Number of nXk arrays of permutations of 0..n*k-1 with rows nondecreasing modulo 5 and columns nondecreasing modulo 6.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 18, 40, 11, 1, 2, 116, 803, 815, 94, 1, 4, 627, 23775, 74070, 22320, 365, 2, 8, 6211, 468540, 3908105, 3432012, 352181, 2891, 4, 16, 59011, 17266449, 530614763
Offset: 1

Views

Author

R. H. Hardin, Nov 21 2015

Keywords

Comments

Table starts
.1....1......1.......1.......1.........2........4.....8.16
.1....2......2......18.....116.......627.....6211.59011
.1....2.....40.....803...23775....468540.17266449
.1...11....815...74070.3908105.530614763
.1...94..22320.3432012
.1..365.352181
.2.2891

Examples

			Some solutions for n=4 k=4
.15..0.13..8....0..6..8.13....0..1.13.14....0..1..7.13....0..6..7..2
.10.12..7..2....1.12..2..7...12..7..2..8...12..2..3.14....1.12..3..8
.11..6..1.14...10..3..4.14....6..3..9..4....6..8..9..4...13.14..9..4
..5..3..4..9....5.15.11..9....5.15.10.11...15..5.10.11...15..5.10.11
		

Crossrefs

Column 1 is A264701.
Row 1 is A264656.

A264837 T(n,k)=Number of nXk arrays of permutations of 0..n*k-1 with rows nondecreasing modulo 5 and columns nondecreasing modulo 7.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 15, 22, 8, 1, 2, 68, 409, 271, 46, 1, 4, 401, 4800, 13814, 2703, 182, 1, 8, 2179, 147550, 1059838, 742363, 61692, 701, 2, 16, 23229, 5692511, 243485517
Offset: 1

Views

Author

R. H. Hardin, Nov 26 2015

Keywords

Comments

Table starts
.1...1.....1......1.......1.........2.......4.....8.16
.1...2.....2.....15......68.......401....2179.23229
.1...2....22....409....4800....147550.5692511
.1...8...271..13814.1059838.243485517
.1..46..2703.742363
.1.182.61692
.1.701
.2

Examples

			Some solutions for n=4 k=4
..0..7..8.14....0..8.14..9....7..8..9.14....0..7..9.14...15..0..8.14
..1..2..4..9....1.12..7..3....0..1.12..2...15..1..3..8...11..1..2..7
.15.10.12..3...15..5..2..4...15.10..6.11....2.12.13..4....5.10.12..9
..5.11..6.13...10..6.11.13....5..3.13..4...10..5..6.11....6..3.13..4
		

Crossrefs

Column 1 is A264791.
Row 1 is A264656.

A335109 Triangle read by rows: T(n,k) is the number of permutations of length n with each cycle of the permutation containing only elements that are identical (mod k), where 1 <= k <= n.

Original entry on oeis.org

1, 2, 1, 6, 2, 1, 24, 4, 2, 1, 120, 12, 4, 2, 1, 720, 36, 8, 4, 2, 1, 5040, 144, 24, 8, 4, 2, 1, 40320, 576, 72, 16, 8, 4, 2, 1, 362880, 2880, 216, 48, 16, 8, 4, 2, 1, 3628800, 14400, 864, 144, 32, 16, 8, 4, 2, 1
Offset: 1

Views

Author

Dennis P. Walsh, May 23 2020

Keywords

Comments

Let [n] denote {1,2,...,n} and let [n](j,k) denote the subset of [n] consisting of all elements of [n] that equal j mod k. The cardinality of [n](j,k) equals ceiling(n/k) for j = 1..(n mod k) and equals floor(n/k) for j > (n mod k). Therefore, upon permuting the elements of each [n](j,k) subset, we obtain T(n,k) = (ceiling(n/k)!)^(n mod k)*(floor(n/k)!)^(k-(n mod k)).

Examples

			Triangle begins:
    1;
    2  1;
    6  2 1;
   24  4 2 1;
  120 12 4 2 1;
  ...
T(6,3) counts the 8 permutations of [6] where all cycle-mates are identical mod 3, namely, (1 4)(2 5)(3 6), (1 4)(2 5)(3)(6), (1 4)(2)(5)(3 6), (1)(4)(2 5)(3 6), (1 4)(2)(5)(3)(6), (1)(4)(2 5)(3)(6), (1)(4)(2)(5)(3 6) and (1)(2)(3)(4)(5)(6).
		

Crossrefs

Programs

  • Maple
    seq(seq((ceil(n/k)!)^(n mod k)*(floor(n/k)!)^(k-(n mod k)), k=1..n), n=1..10);
  • Mathematica
    Table[(Ceiling[n/k]!)^Mod[n, k]*(Floor[n/k]!)^(k - Mod[n, k]), {n, 10}, {k, n}] // Flatten (* Michael De Vlieger, Jun 28 2020 *)

Formula

T(n,k) = (ceiling(n/k)!)^(n mod k)*(floor(n/k)!)^(k-(n mod k)) for 1 <= k <= n.
T(n,1) = A000142(n).
T(n,2) = A010551(n) for n > 1.
T(n,3) = A264557(n) for n > 2.
T(n,4) = A264635(n) for n > 3.
T(n,5) = A264656(n) for n > 4.
T(n,k) = Product_{i=0..k-1} floor((n+i)/k)!. - Alois P. Heinz, May 23 2020
Showing 1-6 of 6 results.