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.

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A358912 Number of finite sequences of integer partitions with total sum n and all distinct lengths.

Original entry on oeis.org

1, 1, 2, 5, 11, 23, 49, 103, 214, 434, 874, 1738, 3443, 6765, 13193, 25512, 48957, 93267, 176595, 332550, 622957, 1161230, 2153710, 3974809, 7299707, 13343290, 24280924, 43999100, 79412942, 142792535, 255826836, 456735456, 812627069, 1440971069, 2546729830
Offset: 0

Views

Author

Gus Wiseman, Dec 07 2022

Keywords

Examples

			The a(1) = 1 through a(4) = 11 sequences:
  (1)  (2)   (3)      (4)
       (11)  (21)     (22)
             (111)    (31)
             (1)(11)  (211)
             (11)(1)  (1111)
                      (11)(2)
                      (1)(21)
                      (2)(11)
                      (21)(1)
                      (1)(111)
                      (111)(1)
		

Crossrefs

The case of set partitions is A007837.
This is the case of A055887 with all distinct lengths.
For distinct sums instead of lengths we have A336342.
The case of twice-partitions is A358830.
The unordered version is A358836.
The version for constant instead of distinct lengths is A358905.
A000041 counts integer partitions, strict A000009.
A063834 counts twice-partitions.
A141199 counts sequences of partitions with weakly decreasing lengths.

Programs

  • Mathematica
    ptnseq[n_]:=Join@@Table[Tuples[IntegerPartitions/@comp],{comp,Join@@Permutations/@IntegerPartitions[n]}];
    Table[Length[Select[ptnseq[n],UnsameQ@@Length/@#&]],{n,0,10}]
  • PARI
    P(n,y) = {1/prod(k=1, n, 1 - y*x^k + O(x*x^n))}
    seq(n) = {my(g=P(n,y)); [subst(serlaplace(p), y, 1) | p<-Vec(prod(k=1, n, 1 + y*polcoef(g, k, y) + O(x*x^n)))]} \\ Andrew Howroyd, Dec 30 2022

Extensions

Terms a(16) and beyond from Andrew Howroyd, Dec 30 2022

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 *)

A336141 Number of ways to choose a strict composition of each part of an integer partition of n.

Original entry on oeis.org

1, 1, 2, 5, 9, 17, 41, 71, 138, 270, 518, 938, 1863, 3323, 6163, 11436, 20883, 37413, 69257, 122784, 221873, 397258, 708142, 1249955, 2236499, 3917628, 6909676, 12130972, 21251742, 36973609, 64788378, 112103360, 194628113, 336713377, 581527210, 1000153063
Offset: 0

Views

Author

Gus Wiseman, Jul 18 2020

Keywords

Comments

A strict composition of n is a finite sequence of distinct positive integers summing to n.

Examples

			The a(1) = 1 through a(5) = 17 ways:
  (1)  (2)      (3)          (4)              (5)
       (1),(1)  (1,2)        (1,3)            (1,4)
                (2,1)        (3,1)            (2,3)
                (2),(1)      (2),(2)          (3,2)
                (1),(1),(1)  (3),(1)          (4,1)
                             (1,2),(1)        (3),(2)
                             (2,1),(1)        (4),(1)
                             (2),(1),(1)      (1,2),(2)
                             (1),(1),(1),(1)  (1,3),(1)
                                              (2,1),(2)
                                              (3,1),(1)
                                              (2),(2),(1)
                                              (3),(1),(1)
                                              (1,2),(1),(1)
                                              (2,1),(1),(1)
                                              (2),(1),(1),(1)
                                              (1),(1),(1),(1),(1)
		

Crossrefs

Multiset partitions of partitions are A001970.
Strict compositions are counted by A032020, A072574, and A072575.
Splittings of partitions are A323583.
Splittings of partitions with distinct sums are A336131.
Partitions:
- Partitions of each part of a partition are A063834.
- Compositions of each part of a partition are A075900.
- Strict partitions of each part of a partition are A270995.
- Strict compositions of each part of a partition are A336141.
Strict partitions:
- Partitions of each part of a strict partition are A271619.
- Compositions of each part of a strict partition are A304961.
- Strict partitions of each part of a strict partition are A279785.
- Strict compositions of each part of a strict partition are A336142.
Compositions:
- Partitions of each part of a composition are A055887.
- Compositions of each part of a composition are A133494.
- Strict partitions of each part of a composition are A304969.
- Strict compositions of each part of a composition are A307068.
Strict compositions:
- Partitions of each part of a strict composition are A336342.
- Compositions of each part of a strict composition are A336127.
- Strict partitions of each part of a strict composition are A336343.
- Strict compositions of each part of a strict composition are A336139.

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(i*(i+1)/2 g(n$2):
    seq(a(n), n=0..38);  # Alois P. Heinz, Jul 31 2020
  • Mathematica
    Table[Length[Join@@Table[Tuples[Join@@Permutations/@Select[IntegerPartitions[#],UnsameQ@@#&]&/@ctn],{ctn,IntegerPartitions[n]}]],{n,0,10}]
    (* Second program: *)
    b[n_, i_, p_] := b[n, i, p] = If[i(i+1)/2 < n, 0,
         If[n==0, p!, b[n, i-1, p] + b[n-i, Min[n-i, i-1], p+1]]];
    g[n_, i_] := g[n, i] = If[n==0 || i==1, 1, g[n, i-1] +
         b[i, i, 0] g[n-i, Min[n-i, i]]];
    a[n_] := g[n, n];
    a /@ Range[0, 38] (* Jean-François Alcover, May 20 2021, after Alois P. Heinz *)

Formula

G.f.: Product_{k >= 1} 1/(1 - A032020(k)*x^k).

A336142 Number of ways to choose a strict composition of each part of a strict integer partition of n.

Original entry on oeis.org

1, 1, 1, 4, 6, 11, 22, 41, 72, 142, 260, 454, 769, 1416, 2472, 4465, 7708, 13314, 23630, 40406, 68196, 119646, 203237, 343242, 586508, 993764, 1677187, 2824072, 4753066, 7934268, 13355658, 22229194, 36945828, 61555136, 102019156, 168474033, 279181966
Offset: 0

Views

Author

Gus Wiseman, Jul 18 2020

Keywords

Comments

A strict composition of n is a finite sequence of distinct positive integers summing to n.

Examples

			The a(1) = 1 through a(5) = 11 ways:
  (1)  (2)  (3)      (4)        (5)
            (1,2)    (1,3)      (1,4)
            (2,1)    (3,1)      (2,3)
            (2),(1)  (3),(1)    (3,2)
                     (1,2),(1)  (4,1)
                     (2,1),(1)  (3),(2)
                                (4),(1)
                                (1,2),(2)
                                (1,3),(1)
                                (2,1),(2)
                                (3,1),(1)
		

Crossrefs

Multiset partitions of partitions are A001970.
Strict compositions are counted by A032020, A072574, and A072575.
Splittings of partitions are A323583.
Splittings of partitions with distinct sums are A336131.
Partitions:
- Partitions of each part of a partition are A063834.
- Compositions of each part of a partition are A075900.
- Strict partitions of each part of a partition are A270995.
- Strict compositions of each part of a partition are A336141.
Strict partitions:
- Partitions of each part of a strict partition are A271619.
- Compositions of each part of a strict partition are A304961.
- Strict partitions of each part of a strict partition are A279785.
- Strict compositions of each part of a strict partition are A336142.
Compositions:
- Partitions of each part of a composition are A055887.
- Compositions of each part of a composition are A133494.
- Strict partitions of each part of a composition are A304969.
- Strict compositions of each part of a composition are A307068.
Strict compositions:
- Partitions of each part of a strict composition are A336342.
- Compositions of each part of a strict composition are A336127.
- Strict partitions of each part of a strict composition are A336343.
- Strict compositions of each part of a strict composition are A336139.

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(i*(i+1)/2 g(n$2):
    seq(a(n), n=0..38);  # Alois P. Heinz, Jul 31 2020
  • Mathematica
    strptn[n_]:=Select[IntegerPartitions[n],UnsameQ@@#&];
    Table[Length[Join@@Table[Tuples[Join@@Permutations/@strptn[#]&/@ctn],{ctn,strptn[n]}]],{n,0,20}]
    (* Second program: *)
    b[n_, i_, p_] := b[n, i, p] = If[i(i+1)/2 < n, 0,
         If[n == 0, p!, b[n, i-1, p] + b[n-i, Min[n-i, i-1], p+1]]];
    g[n_, i_] := g[n, i] = If[i(i+1)/2 < n, 0,
         If[n == 0, 1, g[n, i-1] + b[i, i, 0]*g[n-i, Min[n-i, i-1]]]];
    a[n_] := g[n, n];
    a /@ Range[0, 38] (* Jean-François Alcover, May 20 2021, after Alois P. Heinz *)

Formula

G.f.: Product_{k >= 1} (1 + A032020(k)*x^k).

A358823 Number of odd-length twice-partitions of n into partitions with all odd parts.

Original entry on oeis.org

0, 1, 1, 3, 3, 7, 10, 20, 29, 58, 83, 150, 230, 399, 605, 1037, 1545, 2547, 3879, 6241, 9437, 15085, 22622, 35493, 53438, 82943, 124157, 191267, 284997, 434634, 647437, 979293, 1452182, 2185599, 3228435, 4826596, 7112683, 10575699, 15530404, 22990800, 33651222
Offset: 0

Views

Author

Gus Wiseman, Dec 03 2022

Keywords

Comments

A twice-partition of n is a sequence of integer partitions, one of each part of an integer partition of n.
Also the number of odd-length twice-partitions of n into strict partitions.

Examples

			The a(1) = 1 through a(6) = 10 twice-partitions with all odd parts:
  (1)  (11)  (3)        (31)        (5)              (33)
             (111)      (1111)      (311)            (51)
             (1)(1)(1)  (11)(1)(1)  (11111)          (3111)
                                    (3)(1)(1)        (111111)
                                    (11)(11)(1)      (3)(11)(1)
                                    (111)(1)(1)      (31)(1)(1)
                                    (1)(1)(1)(1)(1)  (11)(11)(11)
                                                     (111)(11)(1)
                                                     (1111)(1)(1)
                                                     (11)(1)(1)(1)(1)
The a(1) = 1 through a(6) = 10 twice-partitions into strict partitions:
  (1)  (2)  (3)        (4)        (5)              (6)
            (21)       (31)       (32)             (42)
            (1)(1)(1)  (2)(1)(1)  (41)             (51)
                                  (2)(2)(1)        (321)
                                  (3)(1)(1)        (2)(2)(2)
                                  (21)(1)(1)       (3)(2)(1)
                                  (1)(1)(1)(1)(1)  (4)(1)(1)
                                                   (21)(2)(1)
                                                   (31)(1)(1)
                                                   (2)(1)(1)(1)(1)
		

Crossrefs

This is the odd-length case of A270995.
Requiring odd sums also gives A279374 aerated.
This is the case of A358824 with all odd parts.
A000009 counts partitions into odd parts.
A027193 counts partitions of odd length.
A063834 counts twice-partitions, strict A296122, row-sums of A321449.
A078408 counts odd-length partitions into odd parts.
A300301 aerated counts twice-partitions with odd sums and parts.
A358334 counts twice-partitions into odd-length partitions.

Programs

  • Mathematica
    twiptn[n_]:=Join@@Table[Tuples[IntegerPartitions/@ptn],{ptn,IntegerPartitions[n]}];
    Table[Length[Select[twiptn[n],OddQ[Length[#]]&&OddQ[Times@@Flatten[#]]&]],{n,0,10}]
  • PARI
    R(u,y) = {1/prod(k=1, #u, 1 - u[k]*y*x^k + O(x*x^#u))}
    seq(n) = {my(u=Vec(eta(x^2 + O(x*x^n))/eta(x + O(x*x^n)) - 1)); Vec(R(u, 1) - R(u, -1), -(n+1))/2} \\ Andrew Howroyd, Dec 31 2022

Formula

G.f.: ((1/Product_{k>=1} (1-A000009(k)*x^k)) - (1/Product_{k>=1} (1+A000009(k)*x^k)))/2. - Andrew Howroyd, Dec 31 2022

Extensions

Terms a(26) and beyond from Andrew Howroyd, Dec 31 2022

A304786 Expansion of Product_{k>=1} (1 - q(k)*x^k), where q(k) = number of partitions of k into distinct parts (A000009).

Original entry on oeis.org

1, -1, -1, -1, 0, 1, -1, 4, 2, 3, 1, 8, -8, 10, -8, -9, -15, -6, -46, -14, -65, -28, 14, -29, -43, -37, 298, 59, 234, 165, 738, 354, 1083, 703, 1944, -2024, 1917, -1085, 3658, -2385, -6421, -7220, 118, -15569, -11604, -19162, -9448, -36140, -24561, -50505, -24807, 47645
Offset: 0

Views

Author

Ilya Gutkovskiy, May 18 2018

Keywords

Comments

Convolution inverse of A270995.

Crossrefs

Programs

  • Mathematica
    nmax = 51; CoefficientList[Series[Product[(1 - PartitionsQ[k] x^k), {k, 1, nmax}], {x, 0, nmax}], x]
    a[n_] := a[n] = If[n == 0, 1, Sum[-Sum[d PartitionsQ[d]^(k/d), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 51}]

Formula

G.f.: Product_{k>=1} (1 - A000009(k)*x^k).

A327552 Number of partitions in all twice partitions of n where the first partition is strict.

Original entry on oeis.org

0, 1, 2, 7, 11, 29, 63, 125, 225, 489, 930, 1704, 3260, 5859, 10868, 20026, 35062, 61660, 111789, 191119, 337432, 585847, 1003876, 1705380, 2921394, 4930357, 8311554, 14013583, 23435178, 38849655, 64847870, 106784912, 175699558, 289676875, 472418418, 772944773
Offset: 0

Views

Author

Alois P. Heinz, Sep 16 2019

Keywords

Examples

			a(3) = 7 = 1+1+1+2+2 counting the partitions in 3, 21, 111, 2|1, 11|1.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(i*(i+1)/2p+[0, p[1]])(
          combinat[numbpart](i)*b(n-i, min(n-i, i-1)))))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..36);
  • Mathematica
    b[n_, i_] := b[n, i] = If[i(i+1)/2Jean-François Alcover, Dec 17 2020, after Alois P. Heinz *)

A358832 Number of twice-partitions of n into partitions of distinct lengths and distinct sums.

Original entry on oeis.org

1, 1, 2, 4, 7, 15, 25, 49, 79, 154, 248, 453, 748, 1305, 2125, 3702, 5931, 9990, 16415, 26844, 43246, 70947, 113653, 182314, 292897, 464614, 739640, 1169981, 1844511, 2888427, 4562850, 7079798, 11064182, 17158151, 26676385, 41075556, 63598025, 97420873, 150043132
Offset: 0

Views

Author

Gus Wiseman, Dec 04 2022

Keywords

Comments

A twice-partition of n is a sequence of integer partitions, one of each part of an integer partition of n.

Examples

			The a(1) = 1 through a(5) = 15 twice-partitions:
  (1)  (2)   (3)      (4)       (5)
       (11)  (21)     (22)      (32)
             (111)    (31)      (41)
             (11)(1)  (211)     (221)
                      (1111)    (311)
                      (21)(1)   (2111)
                      (111)(1)  (11111)
                                (21)(2)
                                (22)(1)
                                (3)(11)
                                (31)(1)
                                (111)(2)
                                (211)(1)
                                (111)(11)
                                (1111)(1)
		

Crossrefs

This is the case of A271619 with distinct lengths.
These multiset partitions are ranked by A326535 /\ A326533.
This is the case of A358830 with distinct sums.
For constant instead of distinct lengths and sums we have A358833.
A063834 counts twice-partitions, strict A296122, row-sums of A321449.
A273873 counts strict trees.

Programs

  • Mathematica
    twiptn[n_]:=Join@@Table[Tuples[IntegerPartitions/@ptn],{ptn,IntegerPartitions[n]}];
    Table[Length[Select[twiptn[n],UnsameQ@@Total/@#&&UnsameQ@@Length/@#&]],{n,0,10}]
  • PARI
    seq(n)={ local(Cache=Map());
      my(g=Vec(-1+1/prod(k=1, n, 1 - y*x^k + O(x*x^n))));
      my(F(m,r,b) = my(key=[m,r,b], z); if(!mapisdefined(Cache,key,&z),
      z = if(r<=0||m==0, r==0, self()(m-1, r, b) + sum(k=1, m, my(c=polcoef(g[m],k)); if(!bittest(b,k)&&c, c*self()(min(m-1,r-m), r-m, bitor(b, 1<Andrew Howroyd, Dec 31 2022

Extensions

Terms a(21) and beyond from Andrew Howroyd, Dec 31 2022

A358834 Number of odd-length twice-partitions of n into odd-length partitions.

Original entry on oeis.org

0, 1, 1, 3, 3, 8, 11, 24, 35, 74, 109, 213, 336, 624, 986, 1812, 2832, 5002, 7996, 13783, 21936, 37528, 59313, 99598, 158356, 262547, 415590, 684372, 1079576, 1759984, 2779452, 4491596, 7069572, 11370357, 17841534, 28509802, 44668402, 70975399, 110907748
Offset: 0

Views

Author

Gus Wiseman, Dec 04 2022

Keywords

Comments

A twice-partition of n (A063834) is a sequence of integer partitions, one of each part of an integer partition of n.

Examples

			The a(1) = 1 through a(6) = 11 twice-partitions:
  (1)  (2)  (3)        (4)        (5)              (6)
            (111)      (211)      (221)            (222)
            (1)(1)(1)  (2)(1)(1)  (311)            (321)
                                  (11111)          (411)
                                  (2)(2)(1)        (21111)
                                  (3)(1)(1)        (2)(2)(2)
                                  (111)(1)(1)      (3)(2)(1)
                                  (1)(1)(1)(1)(1)  (4)(1)(1)
                                                   (111)(2)(1)
                                                   (211)(1)(1)
                                                   (2)(1)(1)(1)(1)
		

Crossrefs

The version for set partitions is A003712.
If the parts are also odd we get A279374.
The version for multiset partitions of integer partitions is the odd-length case of A356932, ranked by A026424 /\ A356935.
This is the odd-length case of A358334.
This is the odd-lengths case of A358824.
For odd sums instead of lengths we have A358826.
The case of odd sums also is the bisection of A358827.
A000009 counts partitions into odd parts.
A027193 counts partitions of odd length.
A063834 counts twice-partitions, strict A296122, row-sums of A321449.
A078408 counts odd-length partitions into odd parts.
A300301 aerated counts twice-partitions with odd sums and parts.

Programs

  • Mathematica
    twiptn[n_]:=Join@@Table[Tuples[IntegerPartitions/@ptn],{ptn,IntegerPartitions[n]}];
    Table[Length[Select[twiptn[n],OddQ[Length[#]]&&OddQ[Times@@Length/@#]&]],{n,0,10}]
  • PARI
    P(n,y) = {1/prod(k=1, n, 1 - y*x^k + O(x*x^n))}
    R(u,y) = {1/prod(k=1, #u, 1 - u[k]*y*x^k + O(x*x^#u))}
    seq(n) = {my(u=Vec(P(n,1)-P(n,-1))/2); Vec(R(u, 1) - R(u, -1), -(n+1))/2} \\ Andrew Howroyd, Dec 30 2022

Formula

G.f.: ((1/Product_{k>=1} (1-A027193(k)*x^k)) - (1/Product_{k>=1} (1+A027193(k)*x^k)))/2. - Andrew Howroyd, Dec 30 2022

Extensions

Terms a(21) and beyond from Andrew Howroyd, Dec 30 2022

A358825 Number of ways to choose a sequence of integer partitions, one of each part of an integer partition of n into odd parts.

Original entry on oeis.org

1, 1, 1, 4, 4, 11, 20, 35, 56, 113, 207, 326, 602, 985, 1777, 3124, 5115, 8523, 15011, 24519, 41571, 71096, 115650, 191940, 320651, 530167, 865781, 1442059, 2358158, 3833007, 6325067, 10243259, 16603455, 27151086, 43734197, 71032191, 115091799, 184492464
Offset: 0

Views

Author

Gus Wiseman, Dec 03 2022

Keywords

Examples

			The a(1) = 1 through a(5) = 11 twice-partitions:
  (1)  (1)(1)  (3)        (3)(1)        (5)
               (21)       (21)(1)       (32)
               (111)      (111)(1)      (41)
               (1)(1)(1)  (1)(1)(1)(1)  (221)
                                        (311)
                                        (2111)
                                        (11111)
                                        (3)(1)(1)
                                        (21)(1)(1)
                                        (111)(1)(1)
                                        (1)(1)(1)(1)(1)
		

Crossrefs

For odd parts instead of sums we have A270995.
For distinct instead of odd sums we have A271619.
Requiring odd length, odd lengths, and odd parts gives A279374 aerated.
For odd lengths instead of sums we have A358334.
The odd-length case is A358826.
A000009 counts partitions into odd parts.
A027193 counts partitions of odd length.
A063834 counts twice-partitions, strict A296122, row-sums of A321449.
A078408 counts odd-length partitions into odd parts.
A300301 aerated counts twice-partitions with odd sums and parts.

Programs

  • Mathematica
    twiptn[n_]:=Join@@Table[Tuples[IntegerPartitions/@ptn],{ptn,IntegerPartitions[n]}];
    Table[Length[Select[twiptn[n],OddQ[Times@@Total/@#]&]],{n,0,10}]

Formula

G.f.: Product_{k odd} 1/(1-A000041(k)*x^k).
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