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 1-3 of 3 results.

A327618 Number A(n,k) of parts in all k-times partitions of n; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 0, 1, 3, 1, 0, 1, 5, 6, 1, 0, 1, 7, 14, 12, 1, 0, 1, 9, 25, 44, 20, 1, 0, 1, 11, 39, 109, 100, 35, 1, 0, 1, 13, 56, 219, 315, 274, 54, 1, 0, 1, 15, 76, 386, 769, 1179, 581, 86, 1, 0, 1, 17, 99, 622, 1596, 3643, 3234, 1417, 128, 1, 0, 1, 19, 125, 939, 2960, 9135, 12336, 10789, 2978, 192, 1
Offset: 0

Views

Author

Alois P. Heinz, Sep 19 2019

Keywords

Comments

Row n is binomial transform of the n-th row of triangle A327631.

Examples

			A(2,2) = 5 = 1+2+2 counting the parts in 2, 11, 1|1.
Square array A(n,k) begins:
  0,  0,   0,    0,     0,     0,     0,      0, ...
  1,  1,   1,    1,     1,     1,     1,      1, ...
  1,  3,   5,    7,     9,    11,    13,     15, ...
  1,  6,  14,   25,    39,    56,    76,     99, ...
  1, 12,  44,  109,   219,   386,   622,    939, ...
  1, 20, 100,  315,   769,  1596,  2960,   5055, ...
  1, 35, 274, 1179,  3643,  9135, 19844,  38823, ...
  1, 54, 581, 3234, 12336, 36911, 93302, 208377, ...
		

Crossrefs

Columns k=0-3 give: A057427, A006128, A327594, A327627.
Rows n=0-3 give: A000004, A000012, A005408, A095794(k+1).
Main diagonal gives A327619.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0],
         `if`(k=0, [1, 1], `if`(i<2, 0, b(n, i-1, k))+
             (h-> (f-> f +[0, f[1]*h[2]/h[1]])(h[1]*
            b(n-i, min(n-i, i), k)))(b(i$2, k-1))))
        end:
    A:= (n, k)-> b(n$2, k)[2]:
    seq(seq(A(n, d-n), n=0..d), d=0..14);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, {1, 0}, If[k == 0, {1, 1}, If[i < 2, 0, b[n, i - 1, k]] + Function[h, Function[f, f + {0, f[[1]] h[[2]]/ h[[1]]}][h[[1]] b[n - i, Min[n - i, i], k]]][b[i, i, k - 1]]]];
    A[n_, k_] := b[n, n, k][[2]];
    Table[A[n, d-n], {d, 0, 14}, {n, 0, d}] // Flatten (* Jean-François Alcover, Apr 30 2020, after Alois P. Heinz *)

Formula

A(n,k) = Sum_{i=0..k} binomial(k,i) * A327631(n,i).

A306187 Number of n-times partitions of n.

Original entry on oeis.org

1, 1, 3, 10, 65, 371, 3780, 33552, 472971, 5736082, 97047819, 1547576394, 32992294296, 626527881617, 15202246707840, 352290010708120, 9970739854456849, 262225912049078193, 8309425491887714632, 250946978120046026219, 8898019305511325083149
Offset: 0

Views

Author

Alois P. Heinz, Jan 27 2019

Keywords

Comments

A k-times partition of n for k > 1 is a sequence of (k-1)-times partitions, one of each part in an integer partition of n. A 1-times partition of n is just an integer partition of n. The only 0-times partition of n is the number n itself. - Gus Wiseman, Jan 27 2019

Examples

			From _Gus Wiseman_, Jan 27 2019: (Start)
The a(1) = 1 through a(3) = 10 partitions:
  (1)  ((2))     (((3)))
       ((11))    (((21)))
       ((1)(1))  (((111)))
                 (((2)(1)))
                 (((11)(1)))
                 (((2))((1)))
                 (((1)(1)(1)))
                 (((11))((1)))
                 (((1)(1))((1)))
                 (((1))((1))((1)))
(End)
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0 or k=0 or i=1,
          1, b(n, i-1, k)+b(i$2, k-1)*b(n-i, min(n-i, i), k))
        end:
    a:= n-> b(n$3):
    seq(a(n), n=0..25);
  • Mathematica
    ptnlevct[n_,k_]:=Switch[k,0,1,1,PartitionsP[n],_,SeriesCoefficient[Product[1/(1-ptnlevct[m,k-1]*x^m),{m,n}],{x,0,n}]];
    Table[ptnlevct[n,n],{n,0,8}] (* Gus Wiseman, Jan 27 2019 *)

Formula

a(n) = A323718(n,n).

A327623 Number of parts in all n-times partitions of n into distinct parts.

Original entry on oeis.org

0, 1, 1, 7, 27, 121, 553, 3865, 24625, 202954, 1519540, 14193455, 132441998, 1381539355, 14096067555, 168745220585, 1961128020387, 25473872598375, 324797436024684, 4647784901400988, 65394584337577858, 1012005650484163962, 15285115573675197704
Offset: 0

Views

Author

Alois P. Heinz, Sep 19 2019

Keywords

Crossrefs

Main diagonal of A327622.
Cf. A327619.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0],
         `if`(k=0, [1, 1], `if`(i*(i+1)/2 (f-> f +[0, f[1]*h[2]/h[1]])(h[1]*
            b(n-i, min(n-i, i-1), k)))(b(i$2, k-1)))))
        end:
    a:= n-> b(n$3)[2]:
    seq(a(n), n=0..23);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = With[{}, If[n == 0, Return[{1, 0}]]; If[k == 0, Return[{1, 1}]]; If[i (i + 1)/2 < n, Return[{0, 0}]]; b[n, i - 1, k] + Function[h, Function[f, f + {0, f[[1]] h[[2]]/h[[1]]}][h[[1]] b[n - i, Min[n - i, i - 1], k]]][b[i, i, k - 1]]];
    a[n_] := b[n, n, n][[2]];
    a /@ Range[0, 23] (* Jean-François Alcover, Dec 09 2020, after Alois P. Heinz *)
Showing 1-3 of 3 results.