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.

Previous Showing 11-19 of 19 results.

A212857 Number of 4 X n arrays with rows being permutations of 0..n-1 and no column j greater than column j-1 in all rows.

Original entry on oeis.org

1, 1, 15, 1135, 271375, 158408751, 191740223841, 429966316953825, 1644839120884915215, 10079117505143103766735, 94135092186827772028779265, 1287215725538576868883610346465, 24929029117106417518788960414909025, 664978827664071363541997348802227351425
Offset: 0

Views

Author

R. H. Hardin, May 28 2012

Keywords

Comments

From Petros Hadjicostas, Sep 08 2019: (Start)
We generalize Daniel Suteu's recurrence from A212856. Notice first that, in the notation of Abramson and Promislow (1978), we have a(n) = R(m=4, n, t=0).
Letting y=0 in Eq. (8), p. 249, of Abramson and Promislow (1978), we get 1 + Sum_{n >= 1} R(m,n,t=0)*x^n/(n!)^m = 1/f(-x), where f(x) = Sum_{i >= 0} (x^i/(i!)^m). Matching coefficients, we get Sum_{s = 1..n} R(m, s, t=0) * (-1)^(s-1) * binomial(n,s)^m = 1, from which the recurrence in the Formula section follows.
(End)

Examples

			Some solutions for n=3:
  1 2 0   1 0 2   1 0 2   2 1 0   2 0 1   2 1 0   1 0 2
  2 1 0   1 0 2   0 2 1   0 2 1   2 1 0   1 0 2   2 1 0
  1 2 0   2 1 0   1 0 2   0 1 2   2 1 0   2 1 0   1 2 0
  2 1 0   0 1 2   2 1 0   2 1 0   1 0 2   2 1 0   2 1 0
		

Crossrefs

Programs

  • Maple
    A212857 := proc(n) sum(z^k/k!^4, k = 0..infinity);
    series(%^x, z=0, n+1): n!^4*coeff(%,z,n); add(abs(coeff(%,x,k)), k=0..n) end:
    seq(A212857(n), n=1..13); # Peter Luschny, May 27 2017
  • Mathematica
    T[n_, k_] := T[n, k] = If[k == 0, 1, -Sum[Binomial[k, j]^n*(-1)^j*T[n, k - j], {j, 1, k}]];
    a[n_] := T[4, n];
    Table[a[n], {n, 0, 13}] (* Jean-François Alcover, Apr 01 2024, after Alois P. Heinz in A212855 *)

Formula

a(n) = (-1)^(n-1) + Sum_{s = 1..n-1} a(s) * (-1)^(n-s-1) * binomial(n,s)^m for n >= 2 with a(1) = 1. Here m = 4. - Petros Hadjicostas, Sep 08 2019
a(n) = (n!)^4 * [x^n] 1 / (1 + Sum_{k>=1} (-x)^k / (k!)^4). (see Petros Hadjicostas's comment on Sep 08 2019) - Seiichi Manyama, Jul 18 2020

Extensions

a(0)=1 prepended by Seiichi Manyama, Jul 18 2020

A212858 Number of 5 X n arrays with rows being permutations of 0..n-1 and no column j greater than column j-1 in all rows.

Original entry on oeis.org

1, 1, 31, 7291, 7225951, 21855093751, 164481310134301, 2675558106868421881, 84853928323286139485791, 4849446032811641059203617551, 469353176282647626764795665676281, 73159514984813223626195834388445570381, 17619138865526260905773841471696025142373661
Offset: 0

Views

Author

R. H. Hardin, May 28 2012

Keywords

Comments

From Petros Hadjicostas, Sep 08 2019: (Start)
We generalize Daniel Suteu's recurrence from A212856. Notice first that, in the notation of Abramson and Promislow (1978), we have a(n) = R(m=5, n, t=0).
Letting y=0 in Eq. (8), p. 249, of Abramson and Promislow (1978), we get 1 + Sum_{n >= 1} R(m,n,t=0)*x^n/(n!)^m = 1/f(-x), where f(x) = Sum_{i >= 0} (x^i/(i!)^m). Matching coefficients, we get Sum_{s = 1..n} R(m, s, t=0) * (-1)^(s-1) * binomial(n,s)^m = 1, from which the recurrence in the Formula section follows.
(End)

Examples

			Some solutions for n=3:
  2 0 1   0 1 2   0 2 1   0 2 1   1 2 0   0 2 1   2 0 1
  2 0 1   2 1 0   0 1 2   0 2 1   0 1 2   1 2 0   2 0 1
  0 1 2   2 0 1   0 2 1   2 1 0   0 1 2   0 1 2   2 1 0
  2 0 1   0 1 2   1 2 0   0 2 1   1 0 2   2 1 0   1 0 2
  1 2 0   0 2 1   2 1 0   1 2 0   0 1 2   2 1 0   2 1 0
		

Crossrefs

Programs

  • Maple
    A212858 := proc(n) sum(z^k/k!^5, k = 0..infinity);
    series(%^x, z=0, n+1): n!^5*coeff(%,z,n); add(abs(coeff(%,x,k)), k=0..n) end:
    seq(A212858(n), n=1..12); # Peter Luschny, May 27 2017
  • Mathematica
    T[n_, k_] := T[n, k] = If[k == 0, 1, -Sum[Binomial[k, j]^n*(-1)^j*T[n, k - j], {j, 1, k}]];
    a[n_] := T[5, n];
    Table[a[n], {n, 0, 12}] (* Jean-François Alcover, Apr 01 2024, after Alois P. Heinz in A212855 *)

Formula

a(n) = (-1)^(n-1) + Sum_{s = 1..n-1} a(s) * (-1)^(n-s-1) * binomial(n,s)^m for n >= 2 with a(1) = 1. Here m = 5. - Petros Hadjicostas, Sep 08 2019
a(n) = (n!)^5 * [x^n] 1 / (1 + Sum_{k>=1} (-x)^k / (k!)^5). (see Petros Hadjicostas's comment on Sep 08 2019) - Seiichi Manyama, Jul 18 2020

Extensions

a(0)=1 prepended by Seiichi Manyama, Jul 18 2020

A212859 Number of 6 X n arrays with rows being permutations of 0..n-1 and no column j greater than column j-1 in all rows.

Original entry on oeis.org

1, 1, 63, 45199, 182199871, 2801736968751, 128645361626874561, 14895038886845467640193, 3842738508408709445398181439, 2009810719756197663340563540778591, 1977945985139308994141721986912910579313, 3448496643225334129810790241492300508936547073
Offset: 0

Views

Author

R. H. Hardin, May 28 2012

Keywords

Comments

From Petros Hadjicostas, Sep 08 2019: (Start)
We generalize Daniel Suteu's recurrence from A212856. Notice first that, in the notation of Abramson and Promislow (1978), we have a(n) = R(m=6, n, t=0).
Letting y=0 in Eq. (8), p. 249, of Abramson and Promislow (1978), we get 1 + Sum_{n >= 1} R(m,n,t=0)*x^n/(n!)^m = 1/f(-x), where f(x) = Sum_{i >= 0} (x^i/(i!)^m). Matching coefficients, we get Sum_{s = 1..n} R(m, s, t=0) * (-1)^(s-1) * binomial(n,s)^m = 1, from which the recurrence in the Formula section follows.
(End)

Examples

			Some solutions for n=3:
  2 0 1   1 0 2   2 0 1   0 1 2   2 1 0   0 1 2   0 1 2
  0 1 2   0 2 1   1 2 0   0 1 2   1 2 0   0 1 2   0 1 2
  1 0 2   2 0 1   2 0 1   2 0 1   1 0 2   1 0 2   2 0 1
  0 2 1   0 1 2   2 0 1   2 0 1   0 1 2   1 2 0   0 1 2
  1 2 0   2 0 1   0 1 2   1 2 0   1 0 2   0 1 2   1 2 0
  2 1 0   1 0 2   0 2 1   0 2 1   0 1 2   2 0 1   1 2 0
		

Crossrefs

Programs

  • Maple
    A212859 := proc(n) sum(z^k/k!^6, k = 0..infinity);
    series(%^x, z=0, n+1): n!^6*coeff(%,z,n); add(abs(coeff(%,x,k)), k=0..n) end:
    seq(A212859(n), n=1..11); # Peter Luschny, May 27 2017
  • Mathematica
    T[n_, k_] := T[n, k] = If[k == 0, 1, -Sum[Binomial[k, j]^n*(-1)^j*T[n, k - j], {j, 1, k}]];
    a[n_] := T[6, n];
    Table[a[n], {n, 0, 12}] (* Jean-François Alcover, Apr 01 2024, after Alois P. Heinz in A212855 *)

Formula

a(n) = (-1)^(n-1) + Sum_{s = 1..n-1} a(s) * (-1)^(n-s-1) * binomial(n,s)^m for n >= 2 with a(1) = 1. Here m = 6. - Petros Hadjicostas, Sep 08 2019
a(n) = (n!)^6 * [x^n] 1 / (1 + Sum_{k>=1} (-x)^k / (k!)^6). (see Petros Hadjicostas's comment on Sep 08 2019) - Seiichi Manyama, Jul 18 2020

Extensions

a(0)=1 prepended by Seiichi Manyama, Jul 18 2020

A212860 Number of 7 X n arrays with rows being permutations of 0..n-1 and no column j greater than column j-1 in all rows.

Original entry on oeis.org

1, 1, 127, 275563, 4479288703, 347190069843751, 96426023622482278621, 78785944892341703819175577, 163925632052722656731213188429183, 777880066963402408939826643081996101263, 7717574897043522397037273525233635595811018377
Offset: 0

Views

Author

R. H. Hardin, May 28 2012

Keywords

Comments

From Petros Hadjicostas, Sep 08 2019: (Start)
We generalize Daniel Suteu's recurrence from A212856. Notice first that, in the notation of Abramson and Promislow (1978), we have a(n) = R(m=7, n, t=0).
Letting y=0 in Eq. (8), p. 249, of Abramson and Promislow (1978), we get 1 + Sum_{n >= 1} R(m,n,t=0)*x^n/(n!)^m = 1/f(-x), where f(x) = Sum_{i >= 0} (x^i/(i!)^m). Matching coefficients, we get Sum_{s = 1..n} R(m, s, t=0) * (-1)^(s-1) * binomial(n,s)^m = 1, from which the recurrence in the Formula section follows.
(End)

Examples

			Some solutions for n=3:
  0 1 2   0 1 2   0 2 1   0 1 2   0 2 1   0 2 1   0 2 1
  1 2 0   0 2 1   0 2 1   1 0 2   0 2 1   1 0 2   2 1 0
  1 0 2   2 1 0   2 0 1   0 1 2   2 0 1   1 0 2   1 2 0
  0 2 1   1 0 2   0 2 1   1 0 2   0 1 2   2 0 1   0 1 2
  2 0 1   2 1 0   1 0 2   2 1 0   1 2 0   0 1 2   1 2 0
  2 1 0   0 1 2   1 0 2   0 1 2   2 0 1   1 0 2   2 1 0
  1 2 0   2 1 0   0 1 2   0 2 1   2 1 0   2 0 1   2 0 1
		

Crossrefs

Programs

  • Maple
    A212860 := proc(n) sum(z^k/k!^7, k = 0..infinity);
    series(%^x, z=0, n+1): n!^7*coeff(%,z,n); add(abs(coeff(%,x,k)), k=0..n) end:
    seq(A212860(n), n=1..10); # Peter Luschny, May 27 2017
  • Mathematica
    T[n_, k_] := T[n, k] = If[k == 0, 1, -Sum[Binomial[k, j]^n*(-1)^j*T[n, k - j], {j, 1, k}]];
    a[n_] := T[7, n];
    Table[a[n], {n, 0, 12}] (* Jean-François Alcover, Apr 01 2024, after Alois P. Heinz in A212855 *)

Formula

a(n) = (-1)^(n-1) + Sum_{s = 1..n-1} a(s) * (-1)^(n-s-1) * binomial(n,s)^m for n >= 2 with a(1) = 1. Here m = 7. - Petros Hadjicostas, Sep 08 2019
a(n) = (n!)^7 * [x^n] 1 / (1 + Sum_{k>=1} (-x)^k / (k!)^7). (see Petros Hadjicostas's comment on Sep 08 2019) - Seiichi Manyama, Jul 18 2020

Extensions

a(0)=1 prepended by Seiichi Manyama, Jul 18 2020

A325305 Irregular triangular array, read by rows: T(n,k) is the sum of the products of distinct multinomial coefficients (n_1 + n_2 + n_3 + ...)!/(n_1! * n_2! * n_3! * ...) taken k at a time, where (n_1, n_2, n_3, ...) runs over all integer partitions of n (n >= 0, 0 <= k <= A070289(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 2, 1, 10, 27, 18, 1, 47, 718, 4416, 10656, 6912, 1, 246, 20545, 751800, 12911500, 100380000, 304200000, 216000000, 1, 1602, 929171, 260888070, 39883405500, 3492052425000, 177328940580000, 5153150631600000, 82577533320000000, 669410956800000000, 2224399449600000000, 1632586752000000000, 1, 11271
Offset: 0

Views

Author

Petros Hadjicostas, Sep 05 2019

Keywords

Comments

This array was inspired by R. H. Hardin's recurrences for the columns of array A212855. Row n has length A070289(n) + 1.
This array differs from array A309951 starting at row n = 7. Array A309951 calculates a similar sum of products of multinomial coefficients, but the multinomial coefficients do not have to be distinct. Row n of array A309951 has length A000041(n) + 1, i.e., one more than the number of partitions of n.
Let P_n be the set of all lists a = (a_1, a_2,..., a_n) of integers a_i >= 0, i = 1,..., n such that 1*a_1 + 2*a_2 + ... + n*a_n = n; i.e., P_n is the set all integer partitions of n. (We use a different notation for partitions than the one in the name of T(n,k).) Then |P_n| = A000041(n) for n >= 0.
For n = 1..6, all the multinomial coefficients n!/((1!)^a_1 * (2!)^a_2 * ... * (n!)^a^n) corresponding to lists (a_1,...,a_n) in P_n are distinct; that is, A000041(n) = A070289(n) for n = 1..6.
For n = 7, the partitions (a_1, a_2, a_3, a_4, a_5, a_6, a_7) = (0, 2, 1, 0, 0, 0, 0) (i.e., 2 + 2 + 3) and (a_1, a_2, a_3, a_4, a_5, a_6, a_7) = (3, 0, 0, 1, 0, 0, 0) (i.e., 1 + 1 + 1 + 4) give the same multinomial coefficient: 210 = 7!/(2!2!3!) = 7!/(1!1!1!4!). Hence, A000041(7) > A070289(7).
Looking at the multinomial coefficients of the integer partitions of n = 8, 9, 10 on pp. 831-832 of Abramowitz and Stegun (1964), we see that, even in these cases, we have A000041(n) > A070289(n).

Examples

			Triangle begins as follows:
  [n=0]: 1,   1;
  [n=1]: 1,   1;
  [n=2]: 1,   3,     2;
  [n=3]: 1,  10,    27,     18;
  [n=4]: 1,  47,   718,   4416,    10656,      6912;
  [n=5]: 1, 246, 20545, 751800, 12911500, 100380000, 304200000, 216000000;
  ...
For example, when n = 3, the integer partitions of 3 are 3, 1+2, 1+1+1, and the corresponding multinomial coefficients are 3!/3! = 1, 3!/(1!2!) = 3, and 3!/(1!1!1!) = 6. They are all distinct. Then T(n=3, k=0) = 1, T(n=3, k=1) = 1 + 3 + 6 = 10, T(n=3, k=2) = 1*3 + 1*6 + 3*6 = 27, and T(n=3, k=3) = 1*3*6 = 18.
Consider the list [1, 7, 21, 35, 42, 105, 140, 210, 420, 630, 840, 1260, 2520, 5040] of the A070289(7) = 15 - 1 = 14 distinct multinomial coefficients corresponding to the 15 integer partitions of 7. Then  T(7,0) = 1, T(7,1) = 11271 (sum of the coefficients), T(7,2) = 46169368 (sum of products of every two different coefficients), T(7,3) = 92088653622 (sum of products of every three different coefficients), and so on. Finally, T(7,14) = 2372695722072874920960000000000 = product of these coefficients.
		

Crossrefs

Programs

  • Maple
    g:= proc(n, i) option remember; `if`(n=0 or i=1, [n!], [{map(x->
          binomial(n, i)*x, g(n-i, min(n-i, i)))[], g(n, i-1)[]}[]])
        end:
    b:= proc(n, m) option remember; `if`(n=0, 1,
          expand(b(n-1, m)*(g(m$2)[n]*x+1)))
        end:
    T:= n->(p->seq(coeff(p, x, i), i=0..degree(p)))(b(nops(g(n$2)), n)):
    seq(T(n), n=0..7);  # Alois P. Heinz, Sep 05 2019
  • Mathematica
    g[n_, i_] := g[n, i] = If[n == 0 || i == 1, {n!}, Union[Map[Function[x, Binomial[n, i] x], g[n - i, Min[n - i, i]]], g[n, i - 1]]];
    b[n_, m_] := b[n, m] = If[n == 0, 1, b[n - 1, m] (g[m, m][[n]] x + 1)];
    T[n_] := CoefficientList[b[Length[g[n, n]], n], x];
    T /@ Range[0, 7] // Flatten (* Jean-François Alcover, May 06 2020, after Maple *)

Formula

Sum_{k=0..A070289(n)} (-1)^k * T(n,k) = 0.

A287314 Triangle read by rows, the coefficients of the polynomials generating the columns of A287316.

Original entry on oeis.org

1, 0, 1, 0, -1, 2, 0, 4, -9, 6, 0, -33, 82, -72, 24, 0, 456, -1225, 1250, -600, 120, 0, -9460, 27041, -30600, 17700, -5400, 720, 0, 274800, -826336, 1011017, -661500, 249900, -52920, 5040, 0, -10643745, 33391954, -43471624, 31149496, -13524000, 3622080, -564480, 40320
Offset: 0

Views

Author

Peter Luschny, May 27 2017

Keywords

Comments

The zeta polynomials for the poset P_n of ordered pairs (S,T) where S,T are subsets of [n] with |S| = |T| ordered component-wise by inclusion. - Geoffrey Critzer, Jan 22 2021

Examples

			Triangle starts:
[0] 1
[1] 0,      1
[2] 0,     -1,       2
[3] 0,      4,      -9,       6
[4] 0,    -33,      82,     -72,      24
[5] 0,    456,   -1225,    1250,    -600,    120
[6] 0,  -9460,   27041,  -30600,   17700,  -5400,    720
[7] 0, 274800, -826336, 1011017, -661500, 249900, -52920, 5040
...
For example let p4(x) = -33*x + 82*x^2 - 72*x^3 + 24*x^4 then p4(n) = A169712(n).
		

Crossrefs

Cf. A287316, A000384 (p2), A169711 (p3), A169712 (p4), A169713 (p5).
Cf. A000275(n), A212855.

Programs

  • Maple
    A287314_row := proc(n) local k; sum(z^k/k!^2, k = 0..infinity);
    series(%^x, z=0, n+1): n!^2*coeff(%,z,n); seq(coeff(%,x,k), k=0..n) end:
    for n from 0 to 8 do print(A287314_row(n)) od;
    A287314_poly := proc(n) local k, x; sum(z^k/k!^2, k = 0..infinity);
    series(%^x, z=0, n+1): unapply(n!^2*coeff(%, z, n), x) end:
    for n from 0 to 7 do A287314_poly(n) od;
  • Mathematica
    nn = 10; e[x_] := Sum[x^n/n!^2, {n, 0, nn}];
    f[list_] := CoefficientList[InterpolatingPolynomial[Table[{i, list[[i]]}, {i, 1, nn}], m], m];Drop[Map[f,Transpose[Table[Table[n!^2, {n, 0, nn}] CoefficientList[
    Series[e[x]^k, {x, 0, nn}], x], {k, 1, nn}]]], -1] // Grid (* Geoffrey Critzer, Jan 22 2021 *)

Formula

Sum_{k=0..n} abs(T(n,k)) = A000275(n) = A212855_row(2).

A340986 Square array read by descending antidiagonals. T(n,k) is the number of ways to separate the columns of an ordered pair of n-permutations (that have been written as a 2 X n array, one atop the other) into k cells so that no cell has a column rise. For n >= 0, k >= 0.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 3, 0, 1, 3, 10, 19, 0, 1, 4, 21, 92, 211, 0, 1, 5, 36, 255, 1354, 3651, 0, 1, 6, 55, 544, 4725, 29252, 90921, 0, 1, 7, 78, 995, 12196, 123903, 873964, 3081513, 0, 1, 8, 105, 1644, 26215, 377904, 4368729, 34555880, 136407699, 0
Offset: 0

Views

Author

Geoffrey Critzer, Feb 01 2021

Keywords

Comments

A column rise (cf. A000275) means a pair of adjacent columns within a cell where each entry in the first column is less than the adjacent entry in the second column. The order of the columns cannot change. The cells are allowed to be empty.

Examples

			Square array T(n,k) begins:
  1,    1,     1,      1,      1,      1, ...
  0,    1,     2,      3,      4,      5, ...
  0,    3,    10,     21,     36,     55, ...
  0,   19,    92,    255,    544,    995, ...
  0,  211,  1354,   4725,  12196,  26215, ...
  0, 3651, 29252, 123903, 377904, 939155, ...
		

References

  • R. P. Stanley, Enumerative Combinatorics, Vol. I, Second Edition, Section 3.13.

Crossrefs

Columns k=0-4 give: A000007, A000275, A336271, A336638, A336639.
Rows n=0-2 give: A000012, A001477, A014105.
Main diagonal gives A336665.

Programs

  • Maple
    T:= (n, k)-> n!^2*coeff(series(1/BesselJ(0, 2*sqrt(x))^k, x, n+1), x, n):
    seq(seq(T(n, d-n), n=0..d), d=0..10);  # Alois P. Heinz, Feb 02 2021
  • Mathematica
    nn = 6; B[n_] := n!^2; e[x_] := Sum[x^n/B[n], {n, 0, nn}];
    Table[Table[B[n], {n, 0, nn}] PadRight[CoefficientList[Series[e[-x]^-k, {x, 0, nn}], x], nn + 1], {k, 0, nn}] // Grid

Formula

Let E(x) = Sum_{n>=0} x^n/n!^2. Then Sum_{n>=0} T(n,k)*x^n/n!^2 = 1/E(-x)^k.
T(n,k) = (n!)^2 * [x^n] 1/BesselJ(0,2*sqrt(x))^k. - Alois P. Heinz, Feb 02 2021
For fixed k>=1, T(n,k) ~ n!^2 * n^(k-1) / ((k-1)! * r^(n + k/2) * BesselJ(1, 2*sqrt(r))^k), where r = BesselJZero(0,1)^2 / 4 = A115368^2/4 = 1.4457964907366961302939989396139517587... - Vaclav Kotesovec, Jul 11 2025

A212806 Number of n X n matrices in which each row is a permutation of [1..n] and which contain no column rises.

Original entry on oeis.org

1, 3, 163, 271375, 21855093751, 128645361626874561, 78785944892341703819175577, 6795588328283070704898044776213094655, 107414633522643325764587104395687638119674465944431, 392471529081605251407320880492124164530148025908765037878553312273, 407934916447631403509359040563002566177814886353044858592046202746464825839911293037
Offset: 1

Views

Author

N. J. A. Sloane, May 27 2012

Keywords

Comments

A column rise in a matrix M = (m_{i,j}) is a value of j such that m_{i,j} < m_{i,j+1} for all i = 1..n.
From Petros Hadjicostas, Aug 26 2019: (Start)
Let R(m,n) := R(m,n,t=0) = A212855(m,n) for m,n >= 1, where R(m,n,t) = LHS of Eq. (6) of Abramson and Promislow (1978, p. 248).
Let P_n be the set of all lists b = (b_1, b_2,..., b_n) of integers b_i >= 0, i = 1,..., n, such that 1*b_1 + 2*b_2 + ... + n*b_n = n; i.e., P_n is the set all integer partitions of n. Then |P_n| = A000041(n) for n >= 0.
We have a(n) = R(n,n) = A212855(n,n) = Sum_{b in P_n} (-1)^(n - Sum_{j=1..n} b_j) * (b_1 + b_2 + ... + b_n)!/(b_1! * b_2! * ... * b_n!) * (n! / ((1!)^b_1 * (2!)^b_2 * ... * (n!)^b_n)^n.
(End)

Examples

			For n=2 the three matrices are [12/21], [21/12], [21/21] (but not [12/12]).
From _Petros Hadjicostas_, Aug 26 2019: (Start)
For example, when n = 3, the integer partitions of 3 are 3, 1+2, and 1+1+1, with corresponding (b_1, b_2, b_3) notation (0,0,1), (1,1,0), and (3,0,0). The corresponding multinomial coefficients are 3!/3! = 1, 3!/(1!*2!) = 3, and 3!/(1!*1!*1!) = 6, while the corresponding quantities (b_1 + b_2 + b_3)!/(b_1!*b_2!*b_3!) are 1, 2, and 1. The corresponding exponents of -1 (i.e., n - Sum_{j=1..n} b_j) are 3 - (0+0+1) = 2, 3 - (1+1+0) = 1, and 3 - (3+0+0) = 0.
It follows that a(n) = (-1)^2 * 1 * 1^3 + (-1)^1 * 2 * 3^3 + (-1)^0 * 1 * 6^3 = 163.
(End)
		

Crossrefs

Programs

  • Maple
    A212806 := proc(n) sum(z^k/k!^n, k=0..infinity);
    series(%^x, z=0, n+1): n!^n*coeff(%,z,n); add(abs(coeff(%,x,k)),k=0..n) end:
    seq(A212806(n), n=1..11); # Peter Luschny, May 27 2017
  • Mathematica
    a[n_] := Module[{s0, s1, s2}, s0 = Sum[z^k/k!^n, {k, 0, n}]; s1 =  Series[s0^x, {z, 0, n + 1}] // Normal; s2 = n!^n*Coefficient[s1, z, n]; Sum[Abs[Coefficient[s2, x, k]], {k, 0, n}]]; Array[a, 11] (* Jean-François Alcover, Feb 27 2018, after Peter Luschny *)
    T[n_, k_] := T[n, k] = If[k == 0, 1, -Sum[Binomial[k, j]^n*(-1)^j*T[n, k-j], {j, 1, k}]];
    a[n_] := T[n, n];
    Table[a[n], {n, 1, 12}] (* Jean-François Alcover, Apr 01 2024, after Alois P. Heinz in A212855 *)

Formula

Abramson and Promislow give a g.f. for R(m,n,t), the number of m X n matrices in which each row is a permutation of [1..n] and which contain exactly t column rises:
1 + Sum_{n>=1} Sum_{t=0..n-1} R(m,n,t) y^t x^n/(n!)^m = (y-1)/(y-f(x(y-1))) where f(x) = Sum_{i>=0} x^i/(i!)^m.

Extensions

Corrected by R. H. Hardin, May 28 2012

A287696 Triangle read by rows, T(n,k) = (n!)^3 * [x^k] [z^n] hypergeom([], [1, 1], z)^x for n>=0, 0<=k<=n.

Original entry on oeis.org

1, 0, 1, 0, -3, 4, 0, 46, -81, 36, 0, -1899, 3916, -2592, 576, 0, 163476, -375375, 305500, -108000, 14400, 0, -25333590, 63002191, -58725000, 26370000, -5832000, 518400, 0, 6412369860, -16976577828, 17470973569, -9168390000, 2636298000, -400075200, 25401600
Offset: 0

Views

Author

Peter Luschny, May 30 2017

Keywords

Comments

The polynomials Sum_{k=0..n} T(n,k) x^k generate the columns of A287698.

Examples

			0: [1]
1: [0,         1]
2: [0,        -3,        4]
3: [0,        46,      -81,        36]
4: [0,     -1899,     3916,     -2592,      576]
5: [0,    163476,  -375375,    305500,  -108000,    14400]
6: [0, -25333590, 63002191, -58725000, 26370000, -5832000, 518400]
		

Crossrefs

T(n,n) = A001044(n).

Programs

  • Maple
    A287696_row := proc(n) local k; hypergeom([],[1,1],z); series(%^x, z=0, n+1):
    n!^3*coeff(%, z, n); seq(coeff(%, x, k), k=0..n) end:
    for n from 0 to 8 do A287696_row(n) od;
    A287696_poly := proc(n) local k, x; hypergeom([],[1,1],z); series(%^x, z=0, n+1):
    unapply(n!^3*coeff(%, z, n), x); end:
    for n from 0 to 7 do A287696_poly(n) od;
  • Mathematica
    T[n_, k_] := (n!)^3 SeriesCoefficient[HypergeometricPFQ[{}, {1, 1}, z]^x, {x, 0, k}, {z, 0, n}];
    Table[T[n, k], {n, 0, 7}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jun 13 2017 *)

Formula

Sum_{k=0..n} T(n,k) = A000012(n).
Sum_{k=0..n} abs(T(n,k)) = A212856(n) = A212855_row(3).
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