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 1-7 of 7 results.

A279785 Number of ways to choose a strict partition of each part of a strict partition of n.

Original entry on oeis.org

1, 1, 1, 3, 4, 7, 11, 18, 28, 47, 71, 108, 166, 252, 382, 587, 869, 1282, 1938, 2832, 4153, 6148, 8962, 12965, 18913, 27301, 39380, 56747, 81226, 115907, 166358, 236000, 334647, 475517, 671806, 947552, 1335679, 1875175, 2630584, 3687589, 5150585, 7183548
Offset: 0

Views

Author

Gus Wiseman, Dec 18 2016

Keywords

Comments

This sequence is obtained from the generalized Euler transform in A266964 by taking f(n) = -1, g(n) = -A000009(n). - Seiichi Manyama, Nov 14 2018

Examples

			The a(6)=11 twice-partitions are:
((6)), ((5)(1)), ((51)), ((4)(2)), ((42)), ((41)(1)),
((3)(2)(1)), ((31)(2)), ((32)(1)), ((321)), ((21)(2)(1)).
		

Crossrefs

Programs

  • Maple
    with(numtheory):
    g:= proc(n) option remember; `if`(n=0, 1, add(add(
          `if`(d::odd, d, 0), d=divisors(j))*g(n-j), j=1..n)/n)
        end:
    b:= proc(n, i) option remember; `if`(n>i*(i+1)/2, 0,
          `if`(n=0, 1, b(n, i-1)+`if`(i>n, 0, g(i)*b(n-i, i-1))))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..70);  # Alois P. Heinz, Dec 20 2016
  • Mathematica
    nn=20;CoefficientList[Series[Product[(1+PartitionsQ[k]x^k),{k,nn}],{x,0,nn}],x]
    (* Second program: *)
    g[n_] := g[n] = If[n==0, 1, Sum[Sum[If[OddQ[d], d, 0], {d, Divisors[j]}]* g[n - j], {j, 1, n}]/n]; b[n_, i_] := b[n, i] = If[n > i*(i + 1)/2, 0, If[n==0, 1, b[n, i-1] + If[i>n, 0, g[i]*b[n-i, i-1]]]]; a[n_] := b[n, n]; Table[a[n], {n, 0, 70}] (* Jean-François Alcover, Feb 07 2017, after Alois P. Heinz *)

Formula

G.f.: Product_{k>0} (1 + A000009(k)*x^k). - Seiichi Manyama, Nov 14 2018

A327622 Number A(n,k) of parts in all k-times partitions of n into distinct parts; 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, 1, 1, 0, 1, 1, 3, 1, 0, 1, 1, 5, 3, 1, 0, 1, 1, 7, 8, 5, 1, 0, 1, 1, 9, 16, 15, 8, 1, 0, 1, 1, 11, 27, 35, 28, 10, 1, 0, 1, 1, 13, 41, 69, 73, 49, 13, 1, 0, 1, 1, 15, 58, 121, 160, 170, 86, 18, 1, 0, 1, 1, 17, 78, 195, 311, 460, 357, 156, 25, 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 A327632.

Examples

			Square array A(n,k) begins:
  0,  0,  0,   0,    0,    0,    0,     0,     0, ...
  1,  1,  1,   1,    1,    1,    1,     1,     1, ...
  1,  1,  1,   1,    1,    1,    1,     1,     1, ...
  1,  3,  5,   7,    9,   11,   13,    15,    17, ...
  1,  3,  8,  16,   27,   41,   58,    78,   101, ...
  1,  5, 15,  35,   69,  121,  195,   295,   425, ...
  1,  8, 28,  73,  160,  311,  553,   918,  1443, ...
  1, 10, 49, 170,  460, 1047, 2106,  3865,  6611, ...
  1, 13, 86, 357, 1119, 2893, 6507, 13182, 24625, ...
		

Crossrefs

Columns k=0-3 give: A057427, A015723, A327605, A327628.
Rows n=0,(1+2),3-5 give: A000004, A000012, A005408, A104249, A005894.
Main diagonal gives: A327623.

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, 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] = 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_, k_] := b[n, n, k][[2]];
    Table[A[n, d - n], {d, 0, 14}, {n, 0, d}] // Flatten (* Jean-François Alcover, Jun 03 2020, after Maple *)

Formula

A(n,k) = Sum_{i=0..k} binomial(k,i) * A327632(n,i).

A327594 Number of parts in all twice partitions of n.

Original entry on oeis.org

0, 1, 5, 14, 44, 100, 274, 581, 1417, 2978, 6660, 13510, 29479, 58087, 120478, 236850, 476913, 916940, 1812498, 3437043, 6657656, 12512273, 23780682, 44194499, 83117200, 152837210, 283431014, 517571202, 949844843, 1719175176, 3127751062, 5618969956, 10133425489
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2019

Keywords

Examples

			a(2) = 5 = 1+2+2 counting the parts in 2, 11, 1|1.
a(3) = 14 = 1+2+3+2+3+3: 3, 21, 111, 2|1, 11|1, 1|1|1.
		

Crossrefs

Programs

  • Maple
    g:= proc(n) option remember; (p-> [p(n), add(p(n-j)*
          numtheory[tau](j), j=1..n)])(combinat[numbpart])
        end:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0],
          `if`(i<2, 0, b(n, i-1)) +(h-> (f-> f +[0, f[1]*
           h[2]/h[1]])(b(n-i, min(n-i, i))*h[1]))(g(i)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..37);
    # second Maple program:
    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-> b(n$2, 2)[2]:
    seq(a(n), n=0..37);
  • 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_] := b[n, n, 2][[2]];
    a /@ Range[0, 37] (* Jean-François Alcover, Dec 05 2020, after Alois P. Heinz *)

A327607 Number of parts in all twice partitions of n where the first partition is strict.

Original entry on oeis.org

0, 1, 3, 11, 21, 58, 128, 276, 516, 1169, 2227, 4324, 8335, 15574, 29116, 55048, 97698, 176291, 323277, 563453, 1005089, 1770789, 3076868, 5293907, 9184885, 15668638, 26751095, 45517048, 76882920, 128738414, 217219751, 360525590, 599158211, 995474365
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2019

Keywords

Examples

			a(3) = 11 = 1+2+3+2+3 counting the parts in 3, 21, 111, 2|1, 11|1.
		

Crossrefs

Programs

  • Maple
    g:= proc(n) option remember; (p-> [p(n), add(p(n-j)*
          numtheory[tau](j), j=1..n)])(combinat[numbpart])
        end:
    b:= proc(n, i) option remember; `if`(i*(i+1)/2 (f-> f+[0, f[1]*
           h[2]/h[1]])(b(n-i, min(n-i, i-1))*h[1]))(g(i))))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..37);
  • Mathematica
    g[n_] := g[n] = {PartitionsP[n], Sum[PartitionsP[n - j] DivisorSigma[0, j], {j, 1, n}]};
    b[n_, i_] := b[n, i] = If[i(i+1)/2 < n, 0, If[n == 0, {1, 0}, Module[{h, f}, h = g[i]; f = b[n - i, Min[n - i, i - 1]] h[[1]]; b[n, i - 1] + f + {0, f[[1]] h[[2]] / h[[1]]}]]];
    a[n_] := b[n, n][[2]];
    a /@ Range[0, 37] (* Jean-François Alcover, Dec 05 2020, after Alois P. Heinz *)

A327608 Number of parts in all twice partitions of n where the second partition is strict.

Original entry on oeis.org

0, 1, 3, 8, 17, 34, 74, 134, 254, 470, 842, 1463, 2620, 4416, 7545, 12749, 21244, 34913, 57868, 93583, 151963, 244602, 391206, 620888, 987344, 1550754, 2435087, 3804354, 5920225, 9162852, 14179754, 21785387, 33436490, 51121430, 77935525, 118384318, 179617794
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2019

Keywords

Examples

			a(3) = 8 = 1+2+2+3 counting the parts in 3, 21, 2|1, 1|1|1.
		

Crossrefs

Programs

  • Maple
    g:= proc(n, i) option remember; `if`(i*(i+1)/2 f+
           [0, f[1]])(g(n-i, min(n-i, i-1)))))
        end:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0],
          `if`(i<2, 0, b(n, i-1)) +(h-> (f-> f +[0, f[1]*
           h[2]/h[1]])(b(n-i, min(n-i, i))*h[1]))(g(i$2)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..37);
  • Mathematica
    g[n_, i_] := g[n, i] = If[i(i+1)/2 < n, 0, If[n == 0, {1, 0}, g[n, i - 1] + Function[f, f + {0, f[[1]]}][g[n - i, Min[n - i, i - 1]]]]];
    b[n_, i_] := b[n, i] = If[n == 0, {1, 0}, If[i < 2, 0, b[n, i - 1]] + Module[{h, f}, h = g[i, i]; f = b[n - i, Min[n - i, i]] h[[1]]; f + {0, f[[1]] h[[2]]/h[[1]]}]];
    a[n_] := b[n, n][[2]];
    a /@ Range[0, 37] (* Jean-François Alcover, Dec 05 2020, after Alois P. Heinz *)

A327553 Number of partitions in all twice partitions of n where both partitions are strict.

Original entry on oeis.org

0, 1, 1, 4, 6, 11, 20, 33, 57, 100, 165, 254, 417, 649, 1039, 1648, 2540, 3836, 6020, 9035, 13645, 20752, 31054, 45993, 68668, 101511, 149525, 220132, 321614, 468031, 684124, 989703, 1427054, 2064859, 2964987, 4254028, 6090453, 8686574, 12366583, 17598885
Offset: 0

Views

Author

Alois P. Heinz, Sep 16 2019

Keywords

Examples

			a(3) = 4 = 1+1+2 counting the partitions in 3, 21, 2|1.
		

Crossrefs

Programs

  • Maple
    g:= proc(n) option remember; `if`(n=0, 1, add(g(n-j)*add(
         `if`(d::odd, d, 0), d=numtheory[divisors](j)), j=1..n)/n)
        end:
    b:= proc(n, i) option remember; `if`(i*(i+1)/2 p+[0, p[1]])(
           g(i)*b(n-i, min(n-i, i-1)))))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..42);
  • Mathematica
    g[n_] := g[n] = If[n == 0, 1, Sum[g[n - j] Sum[If[OddQ[d], d, 0], {d, Divisors[j]}], {j, 1, n}]/n];
    b[n_, i_] := b[n, i] = If[i(i+1)/2 < n, {0, 0}, If[n==0, {1, 0}, b[n, i-1] + Function[p, p + {0, p[[1]]}][g[i] b[n-i, Min[n-i, i-1]]]]];
    a[n_] := b[n, n][[2]];
    a /@ Range[0, 42] (* Jean-François Alcover, Dec 18 2020, after Alois P. Heinz *)

A327795 Number of parts in all proper twice partitions of n into distinct parts.

Original entry on oeis.org

0, 0, 0, 3, 6, 13, 30, 61, 121, 210, 353, 600, 989, 1628, 2667, 4205, 6514, 10406, 15893, 24322, 37516, 56824, 85102, 128420, 191579, 284898, 422839, 622721, 913006, 1345320, 1958269, 2843788, 4140170, 5983662, 8632808, 12433730, 17830728, 25527909, 36516161
Offset: 1

Views

Author

Alois P. Heinz, Sep 25 2019

Keywords

Examples

			a(4) = 3:
  4 -> 31 -> 211   (3 parts)
		

Crossrefs

Column k=2 of A327632.
Cf. A327605.

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-> (k-> add(b(n$2, i)[2]*(-1)^(k-i)*binomial(k, i), i=0..k))(2):
    seq(a(n), n=1..41);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = With[{}, If[n == 0, {1, 0}, If[k == 0, {1, 1}, If[i (i + 1)/2 < n, {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]]]]]];
    T[n_, k_] := Sum[b[n, n, i][[2]] (-1)^(k - i) Binomial[k, i], {i, 0, k}];
    a[n_] := T[n, 2];
    Array[a, 41] (* Jean-François Alcover, Dec 09 2020, after Alois P. Heinz *)
Showing 1-7 of 7 results.