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.

A147984 Column 5 of A144512.

Original entry on oeis.org

1, 2431, 4061871, 7528988476, 15467641899285, 34155922905682979, 79397199549271412737, 191739533381111401455478, 476872353039366288373555323
Offset: 0

Views

Author

N. J. A. Sloane, May 13 2009

Keywords

Crossrefs

A149187 a(n) = total number of partitions of [1, 2, ..., k] into exactly n blocks, each of size 1, 2, ..., 6, for 0 <= k <= 6n.

Original entry on oeis.org

1, 6, 1709, 9268549, 295887993624, 34155922905682979, 10893033763705794846727, 8064519699524417149584982475, 12261371699318896159811165091392898, 34949877647533654983311522321749656046802, 174047342897498341701547082125166096889157924610, 1431472607165249058159939223685478666695036430843693596
Offset: 0

Views

Author

N. J. A. Sloane, May 13 2009

Keywords

Comments

Also, number of scenarios in the Gift Exchange Game when a gift can be stolen at most 5 times. - N. J. A. Sloane, Jan 25 2017

Crossrefs

Cf. A144512.
The gift scenarios sequences when a gift can be stolen at most s times, for s = 1..9, are A001515, A144416, A144508, A144509, A149187, A281358, A281359, A281360, A281361.

Programs

  • Maple
    with(combinat):
    b:= proc(n, i, t) option remember; `if`(t*i add(b(k, 6, n), k=0..6*n):
    seq(a(n), n=0..20);  # Alois P. Heinz, Sep 17 2015
  • Mathematica
    multinomial[n_, k_List] := n!/Times @@ (k!); b[n_, i_, t_] := b[n, i, t] = If[t*i < n, 0, If[n == 0, If[t == 0, 1, 0], Sum[b[n-i*j, i-1, t-j]* multinomial[n, Prepend[Array[i&, j], n-i*j]]/j!, {j, 0, Min[t, n/i]}]]]; a[n_] := Sum[b[k, 6, n], {k, 0, 6*n}];  Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Dec 06 2016 after Alois P. Heinz *)
  • PARI
    {a(n) = sum(i=n, 6*n, i!*polcoef(sum(j=1, 6, x^j/j!)^n, i))/n!} \\ Seiichi Manyama, May 22 2019

A144510 Array T(n,k) (n >= 1, k >= 0) read by downwards antidiagonals: T(n,k) = total number of partitions of [1, 2, ..., i] into exactly k nonempty blocks, each of size at most n, for any i in the range n <= i <= k*n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 7, 3, 1, 1, 37, 31, 4, 1, 1, 266, 842, 121, 5, 1, 1, 2431, 45296, 18252, 456, 6, 1, 1, 27007, 4061871, 7958726, 405408, 1709, 7, 1, 1, 353522, 546809243, 7528988476, 1495388159, 9268549, 6427, 8, 1
Offset: 1

Views

Author

David Applegate and N. J. A. Sloane, Dec 15 2008, Jan 30 2009

Keywords

Examples

			Array begins:
1, 1,    1,       1,            1,                 1,                       1, ...
1, 2,    7,      37,          266,              2431,                   27007, ...
1, 3,   31,     842,        45296,           4061871,               546809243, ...
1, 4,  121,   18252,      7958726,        7528988476,          13130817809439, ...
1, 5,  456,  405408,   1495388159,    15467641899285,      361207016885536095, ...
1, 6, 1709, 9268549, 295887993624, 34155922905682979, 10893033763705794846727, ...
...
		

Crossrefs

For the transposed array see A144512.
Rows include A001515, A144416, A144508, A144509.
Columns include A048775, A144511.
A(n+1,n) gives A281901.
A(n,n) gives A308296.
Cf. A308292.

Programs

  • Maple
    b := proc(n, i, k) local r;
    option remember;
    if n = i then 1;
    elif i < n then 0;
    elif n < 1 then 0;
    else add( binomial(i-1,r)*b(n-1,i-1-r,k), r=0..k);
    end if;
    end proc;
    T:=proc(n,k); add(b(n,i,k),i=0..(k+1)*n); end proc;
    # Peter Luschny, Apr 26 2011
    A144510 := proc(n, k) local m;
    add(m!*coeff(expand((exp(x)*GAMMA(n+1,x)/GAMMA(n+1)-1)^k),x,m),m=k..k*n)/k! end: for row from 1 to 6 do seq(A144510(row, col), col = 0..5) od;
  • Mathematica
    multinomial[n_, k_List] := n!/Times @@ (k!); t[n_, k_] := Module[{i, ik}, ik = Array[i, k]; 1/k!* Sum[multinomial[Total[ik], ik], Evaluate[Sequence @@ Thread[{ik, 1, n}]]]]; Table[t[n-k, k], {n, 1, 10}, {k, n-1, 0, -1}] // Flatten (* Jean-François Alcover, Jan 14 2014 *)

Formula

T(n,k) = (1/k!)*Sum_{i_1=1..n} Sum_{i_2=1..n} ... Sum_{i_k=1..n} multinomial(i_1+i_2+...+i_k; i_1, i_2, ..., i_k).
T(n,k) = (1/k!)*Sum_{m=k..k*n} m! [x^m](e^x Gamma(n+1,x)/Gamma(n+1)-1)^k. Here [x^m]f(x) is the coefficient of x^m in the series expansion of f(x). - Peter Luschny, Apr 26 2011

A144662 a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} Sum_{l=1..n} (i+j+k+l)!/(4!*i!*j!*k!*l!).

Original entry on oeis.org

0, 1, 266, 45296, 7958726, 1495388159, 295887993624, 60790021361170, 12845435390707724, 2774049143394729653, 609542744597785306189, 135840016223787254538508, 30629983532857972983331740, 6975352854342057056747327899, 1602003695575764851150428242804, 370631496919828403109950449644134
Offset: 0

Views

Author

N. J. A. Sloane, Feb 01 2009

Keywords

Crossrefs

Column 4 of A144512. Cf. A144660, A144661.

Programs

  • Maple
    f:=n->add( add( add( add( (i+j+k+l)!/(4!*i!*j!*k!*l!), i=1..n),j=1..n),k=1..n),l=1..n); [seq(f(n),n=0..16)];
  • Mathematica
    a[n_] := Sum[(i+j+k+l)!/(4! i! j! k! l!), {i, n}, {j, n}, {k, n}, {l, n}];
    Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Sep 05 2018 *)
    Table[(Binomial[2*n + 2, n + 1] - 2*(1 + n) + Sum[(1 + k + l + 2*n)! HypergeometricPFQ[{1, -1 - k - l - n, -n}, {-1 - k - l - 2*n, -k - l - n}, 1]/((1 + k + l + n) k! l! (n!)^2) - (2*(1 + k + l + n)!)/((1 + k + l) k! l! n!), {k, 1, n}, {l, 1, n}])/24, {n, 0, 15}] (* Vaclav Kotesovec, Apr 04 2019 *)

A281901 Number of scenarios in the Gift Exchange Game with n players and n wrapped gifts when a gift can be stolen at most n times.

Original entry on oeis.org

1, 2, 31, 18252, 1495388159, 34155922905682979, 350521520018942991464535019, 2371013832433361706367594400829713564440, 14584126149704606223764458141727351569547933381159988406, 107640669875812795238625627484701500354901860426640161278022882392148747562
Offset: 0

Views

Author

Alois P. Heinz, Feb 01 2017

Keywords

Comments

Also total number of partitions of [k] into exactly n nonempty blocks, each of size at most n+1, for any k in the range n <= k <= n^2+n.

Crossrefs

Programs

  • Maple
    with(combinat):
    b:= proc(n, i, t) option remember; `if`(t*i add(b(j, n+1, n), j=0..(n+1)*n):
    seq(a(n), n=0..10);
  • Mathematica
    multinomial[n_, k_List] := n!/Times @@ (k!); b[n_, i_, t_] := b[n, i, t] = If[t*iJean-François Alcover, Mar 13 2017, translated from Maple *)

Formula

a(n) = A144510(n+1,n) = A144512(n,n).

A308296 a(n) = (1/n!) * Sum_{i_1=1..n} Sum_{i_2=1..n} ... Sum_{i_n=1..n} multinomial(i_1+i_2+...+i_n; i_1, i_2, ... , i_n).

Original entry on oeis.org

1, 1, 7, 842, 7958726, 15467641899285, 10893033763705794846727, 4247805448772073978048752721163278, 1299618941291522676629215597535104557826094801396, 419715170056359079715862408734598208208707081189266290220651371206
Offset: 0

Views

Author

Seiichi Manyama, May 19 2019

Keywords

Examples

			a(2) = (1/2) * (binomial(1+1,1) + binomial(1+2,2) + binomial(2+1,1) + binomial(2+2,2)) = 7.
		

Crossrefs

Programs

  • PARI
    {a(n) = sum(i=n, n^2, i!*polcoef(sum(j=1, n, x^j/j!)^n, i))/n!}

Formula

a(n) = A144510(n,n).
Showing 1-6 of 6 results.