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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A356842 Numbers k such that the k-th composition in standard order does not cover an interval of positive integers (not gapless).

Original entry on oeis.org

9, 12, 17, 19, 24, 25, 28, 33, 34, 35, 39, 40, 48, 49, 51, 56, 57, 60, 65, 66, 67, 69, 70, 71, 73, 76, 79, 80, 81, 88, 96, 97, 98, 99, 100, 103, 104, 112, 113, 115, 120, 121, 124, 129, 130, 131, 132, 133, 134, 135, 137, 138, 139, 140, 141, 142, 143, 144, 145
Offset: 1

Views

Author

Gus Wiseman, Sep 01 2022

Keywords

Comments

The k-th composition in standard order (graded reverse-lexicographic, A066099) is obtained by taking the set of positions of 1's in the reversed binary expansion of k, prepending 0, taking first differences, and reversing again. This gives a bijective correspondence between nonnegative integers and integer compositions.

Examples

			The terms and their corresponding standard compositions begin:
   9: (3,1)
  12: (1,3)
  17: (4,1)
  19: (3,1,1)
  24: (1,4)
  25: (1,3,1)
  28: (1,1,3)
  33: (5,1)
  34: (4,2)
  35: (4,1,1)
  39: (3,1,1,1)
  40: (2,4)
  48: (1,5)
  49: (1,4,1)
  51: (1,3,1,1)
  56: (1,1,4)
  57: (1,1,3,1)
  60: (1,1,1,3)
		

Crossrefs

See link for sequences related to standard compositions.
An unordered version is A073492, complement A073491.
These compositions are counted by the complement of A107428.
The complement is A356841.
The gapless but non-initial version is A356843, unordered A356845.
A356230 ranks gapless factorization lengths, firsts A356603.
A356233 counts factorizations into gapless numbers.
A356844 ranks compositions with at least one 1.

Programs

  • Mathematica
    nogapQ[m_]:=m=={}||Union[m]==Range[Min[m],Max[m]];
    stc[n_]:=Differences[Prepend[Join@@Position[Reverse[IntegerDigits[n,2]],1],0]]//Reverse;
    Select[Range[0,100],!nogapQ[stc[#]]&]

A374147 Number of complete Carlitz compositions of n.

Original entry on oeis.org

1, 0, 2, 1, 1, 8, 7, 9, 20, 49, 72, 115, 202, 349, 695, 1171, 2009, 3530, 6203, 10818, 19320, 33961, 59449, 104349, 183370, 321635, 564081, 992513, 1741441, 3057547, 5363570, 9410785, 16516575, 28967505, 50798456, 89106542, 156276871, 274037619, 480437247, 842350671, 1476760717, 2588651452, 4537418431, 7952741429, 13938276465
Offset: 1

Views

Author

John Tyler Rascoe, Jun 28 2024

Keywords

Comments

These are integer compositions such that no adjacent parts are equal and their set of parts covers an initial interval.

Examples

			a(7) = 7 counts: (1,2,1,3), (1,2,3,1), (1,3,2,1), (1,3,1,2), (2,1,3,1), (3,2,1,2), (1,2,1,2,1).
		

Crossrefs

Programs

  • PARI
    Ca_x(s,N)={my(x='x+O('x^N), g=if(#s <1,1, sum(i=1,#s, (Ca_x(s[^i],N) * x^(s[i])/(1+x^(s[i]))))/(1-sum(i=1,#s, (x^(s[i]))/(1+x^(s[i])))))); return(g)}
    B_x(N)={my(x='x+O('x^N), j=1, h=0); while((j*(j+1))/2 <= N, h += Ca_x([1..j],N+1); j+=1); my(a = Vec(h)); vector(N,i,a[i])}
    B_x(45)

Formula

G.f.: Sum_{k>0} Ca({1..k},x) where Ca({s},x) = Sum_{i in {s}} ( (Ca({s}-{i},x)*x^i)/(1 + x^i) )/(1 - Sum_{i in {s}} ( (x^i)/(1 + x^i) )) is the g.f. for Carlitz compositions such that their set of parts equals {s} with Ca({},x) = 1.

A356604 Number of integer compositions of n into odd parts covering an initial interval of odd positive integers.

Original entry on oeis.org

1, 1, 1, 1, 3, 4, 5, 9, 13, 24, 40, 61, 101, 160, 257, 415, 679, 1103, 1774, 2884, 4656, 7517, 12165, 19653, 31753, 51390, 83134, 134412, 217505, 351814, 569081, 920769, 1489587, 2409992, 3899347, 6309059, 10208628, 16518910, 26729830, 43254212, 69994082
Offset: 0

Views

Author

Gus Wiseman, Aug 30 2022

Keywords

Examples

			The a(1) = 1 through a(8) = 13 compositions:
  (1)  (11)  (111)  (13)    (113)    (1113)    (133)      (1133)
                    (31)    (131)    (1131)    (313)      (1313)
                    (1111)  (311)    (1311)    (331)      (1331)
                            (11111)  (3111)    (11113)    (3113)
                                     (111111)  (11131)    (3131)
                                               (11311)    (3311)
                                               (13111)    (111113)
                                               (31111)    (111131)
                                               (1111111)  (111311)
                                                          (113111)
                                                          (131111)
                                                          (311111)
                                                          (11111111)
The a(9) = 24 compositions:
  (135)  (11133)  (1111113)  (111111111)
  (153)  (11313)  (1111131)
  (315)  (11331)  (1111311)
  (351)  (13113)  (1113111)
  (513)  (13131)  (1131111)
  (531)  (13311)  (1311111)
         (31113)  (3111111)
         (31131)
         (31311)
         (33111)
		

Crossrefs

The case of partitions is A053251, ranked by A356232 and A356603.
These compositions are ranked by the intersection of A060142 and A333217.
This is the odd initial case of A107428.
This is the odd restriction of A107429.
This is the normal/covering case of A324969 (essentially A000045).
The non-initial version is A356605.
A000041 counts partitions, compositions A011782.
A055932 lists numbers with prime indices covering an initial interval.
A066208 lists numbers with all odd prime indices, counted by A000009.

Programs

  • Mathematica
    normQ[m_]:=Or[m=={},Union[m]==Range[Max[m]]];
    Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],normQ[(#+1)/2]&]],{n,0,15}]

Extensions

More terms from Alois P. Heinz, Sep 01 2022

A356846 Number of integer compositions of n into parts not covering an interval of positive integers.

Original entry on oeis.org

0, 0, 0, 0, 2, 5, 11, 25, 57, 115, 236, 482, 978, 1986, 4003, 8033, 16150, 32402, 64943, 130207, 260805, 522123, 1045168, 2091722, 4185431, 8374100, 16753538, 33515122, 67042865, 134106640, 268246886, 536549760, 1073194999, 2146553011, 4293391411, 8587283895
Offset: 0

Views

Author

Gus Wiseman, Sep 03 2022

Keywords

Examples

			The a(0) = 0 through a(6) = 8 compositions:
  .  .  .  .  (13)  (14)   (15)
              (31)  (41)   (24)
                    (113)  (42)
                    (131)  (51)
                    (311)  (114)
                           (141)
                           (411)
                           (1113)
                           (1131)
                           (1311)
                           (3111)
		

Crossrefs

The complement is counted by A107428, initial A107429.
The case of partitions is A239955, ranked by A073492, initial A053251, complement A034296.
These compositions are ranked by A356842, complement A356841.
A000041 counts partitions, compositions A011782.
A066208 lists numbers with all odd prime indices, counted by A000009.
A073491 lists numbers with gapless prime indices, initial A055932.

Programs

  • Mathematica
    gappyQ[m_]:=And[m!={},Union[m]!=Range[Min[m],Max[m]]];
    Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],gappyQ]],{n,0,15}]

Formula

a(n) = A011782(n) - A107428(n).

A374726 Number of gap-free Carlitz compositions of n.

Original entry on oeis.org

1, 1, 3, 2, 4, 9, 11, 11, 29, 53, 82, 129, 215, 389, 726, 1237, 2079, 3660, 6386, 11127, 19719, 34658, 60358, 105776, 185641, 324822, 569565, 999824, 1753763, 3075263, 5390839, 9452903, 16579307, 29065205, 50947822, 89330076, 156628094, 274559046, 481250343
Offset: 1

Views

Author

John Tyler Rascoe, Jul 17 2024

Keywords

Comments

These are integer compositions such that no adjacent parts are equal and their set of parts covers some interval.

Examples

			a(6) = 9 counts: (1,2,1,2), (2,1,2,1), (1,2,3), (1,3,2), (2,1,3), (2,3,1), (3,1,2), (3,2,1), (6).
		

Crossrefs

Programs

  • PARI
    Ca_x(s, N)={my(x='x+O('x^N), g=if(#s <1, 1, sum(i=1, #s, (Ca_x(s[^i], N) * x^(s[i])/(1+x^(s[i]))))/(1-sum(i=1, #s, (x^(s[i]))/(1+x^(s[i])))))); return(g)}
    B_x(N)={my(x='x+O('x^N), j=1, h=0); while((j*(j+1))/2 <= N, for(k=0,N, h += Ca_x([(1+k)..(j+k)], N+1)); j++); my(a = Vec(h)); vector(N, i, a[i])}
    B_x(20)

A356605 Number of integer compositions of n into odd parts covering an interval of odd positive integers.

Original entry on oeis.org

1, 1, 1, 2, 3, 5, 6, 10, 15, 26, 41, 65, 104, 164, 262, 424, 687, 1112, 1792, 2898, 4677, 7556, 12197, 19699, 31836, 51466, 83234, 134593, 217674, 352057, 569452, 921165, 1490173, 2410784, 3900288, 6310436, 10210358, 16521108, 26733020, 43258086, 69999295
Offset: 0

Views

Author

Gus Wiseman, Aug 31 2022

Keywords

Examples

			The a(1) = 1 through a(8) = 15 compositions:
  (1)  (11)  (3)    (13)    (5)      (33)      (7)        (35)
             (111)  (31)    (113)    (1113)    (133)      (53)
                    (1111)  (131)    (1131)    (313)      (1133)
                            (311)    (1311)    (331)      (1313)
                            (11111)  (3111)    (11113)    (1331)
                                     (111111)  (11131)    (3113)
                                               (11311)    (3131)
                                               (13111)    (3311)
                                               (31111)    (111113)
                                               (1111111)  (111131)
                                                          (111311)
                                                          (113111)
                                                          (131111)
                                                          (311111)
                                                          (11111111)
		

Crossrefs

These compositions are ranked by the intersection of A060142 and A356841.
Before restricting to odds we have A107428, initial A107429.
The not necessarily gapless version is A324969 (essentially A000045).
The strict case is A332032.
The initial case is A356604.
The case of partitions is A356737, initial A053251 (ranked by A356232).
A000041 counts partitions, compositions A011782.
A066208 lists numbers with all odd prime indices, counted by A000009.
A073491 lists numbers with gapless prime indices, initial A055932.

Programs

  • Mathematica
    nogapQ[m_]:=m=={}||Union[m]==Range[Min[m],Max[m]];
    Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], And@@OddQ/@#&&nogapQ[(#+1)/2]&]],{n,0,15}]

Extensions

More terms from Alois P. Heinz, Sep 01 2022

A371417 Triangle read by rows: T(n,k) is the number of complete compositions of n with k parts.

Original entry on oeis.org

1, 0, 1, 0, 0, 1, 0, 0, 2, 1, 0, 0, 0, 3, 1, 0, 0, 0, 3, 4, 1, 0, 0, 0, 6, 6, 5, 1, 0, 0, 0, 0, 16, 10, 6, 1, 0, 0, 0, 0, 12, 30, 15, 7, 1, 0, 0, 0, 0, 12, 35, 50, 21, 8, 1, 0, 0, 0, 0, 24, 50, 75, 77, 28, 9, 1, 0, 0, 0, 0, 0, 90, 126, 140, 112, 36, 10, 1
Offset: 0

Views

Author

John Tyler Rascoe, Mar 23 2024

Keywords

Comments

A composition (ordered partition) is complete if the set of parts both covers an interval (is gap-free) and contains 1.

Examples

			The triangle begins:
    k=0  1  2  3   4   5   6   7   8   9  10
n=0:  1;
n=1:  0, 1;
n=2:  0, 0, 1;
n=3:  0, 0, 2, 1;
n=4:  0, 0, 0, 3,  1;
n=5:  0, 0, 0, 3,  4,  1;
n=6:  0, 0, 0, 6,  6,  5,  1;
n=7:  0, 0, 0, 0, 16, 10,  6,  1;
n=8:  0, 0, 0, 0, 12, 30, 15,  7,  1;
n=9:  0, 0, 0, 0, 12, 35, 50, 21,  8,  1;
n=10: 0, 0, 0, 0, 24, 50, 75, 77, 28,  9,  1;
...
For n = 5 there are a total of 8 complete compositions:
  T(5,3) = 3: (221), (212), (122)
  T(5,4) = 4: (2111), (1211), (1121), (1112)
  T(5,5) = 1: (11111)
		

Crossrefs

A107428 counts gap-free compositions.
A251729 counts gap-free but not complete compositions.
Cf. A107429 (row sums give complete compositions of n), A000670 (column sums), A152947 (number of nonzero terms per column).

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(n=0,
         `if`(i=0, t!, 0), `if`(i<1 or n (p-> seq(coeff(p, x, i), i=0..n))(add(b(n, i, 0), i=0..n)):
    seq(T(n), n=0..12);  # Alois P. Heinz, Apr 03 2024
  • PARI
    G(N)={ my(z='z+O('z^N)); Vec(sum(i=1,N,z^(i*(i+1)/2)*t^i*prod(j=1,i,sum(k=0,N, (z^(j*k)*t^k)/(k+1)!))))}
    my(v=G(10)); for(n=0, #v, if(n<1,print([1]), my(p=v[n], r=vector(n+1)); for(k=0, n, r[k+1] =k!*polcoeff(p, k)); print(r)))

Formula

T(n,k) = k!*[z^n*t^k] Sum_{i>0} z^(i*(i+1)/2)*t^i * Product_{j=1..i} Sum_{k>=0} (z^(j*k)*t^k)/(k+1)!.

A374727 Number of n-color complete compositions of n.

Original entry on oeis.org

1, 1, 1, 1, 7, 13, 45, 91, 233, 477, 1079, 2205, 4709, 10299, 22393, 52005, 125055, 310373, 799677, 2096699, 5556681, 14806685, 39417431, 104570549, 276027337, 724183555, 1887993925, 4891368373, 12595644523, 32252683453, 82146468813, 208225916203, 525472131209
Offset: 1

Views

Author

John Tyler Rascoe, Jul 17 2024

Keywords

Comments

These are integer compositions whose set of parts covers an initial interval and contains k colors of each part k.

Examples

			a(6) = 13 counts: (1,1,1,1,1,1) and the 12 permutations of parts 1, 1, 2_a, and 2_b.
		

Crossrefs

Programs

  • PARI
    colr(x,y)={my(r=y-x+1, v=[x..y], z = vector(r*(r+(1+(x-1)*2))/2), k=1); for(i=1,#v,for(j=1,v[i],z[k]=v[i]; k++)); return(z)}
    C_x(s,N)={my(x='x+O('x^N), g=if(#s <1,1, sum(i=1,#s, C_x(s[^i],N) * x^(s[i]) )/(1-sum(i=1,#s, x^(s[i]))))); return(g)}
    B_x(N)={my(x='x+O('x^N), j=1, h=0, s=colr(1,j)); while(vecsum(s) <= N, h += C_x(s,N+1); j++;s=colr(1,j)); my(a = Vec(h)); vector(N, i, a[i])}
    B_x(25)

A374728 Number of n-color gap-free compositions of n.

Original entry on oeis.org

1, 1, 1, 3, 7, 19, 45, 105, 239, 507, 1079, 2303, 4829, 10425, 23263, 53363, 127995, 318983, 816057, 2133241, 5640135, 14975051, 39772751, 105322879, 277547989, 727276225, 1894282195, 4903985955, 12621154315, 32302574959, 82248961437, 208426306113, 525884062427
Offset: 1

Views

Author

John Tyler Rascoe, Jul 17 2024

Keywords

Comments

These are integer compositions whose set of parts covers some interval and contains k colors of each part k.

Examples

			a(5) = 7 counts: (1,1,1,1,1), (1,2_a,2_b), (1,2_b,2_a), (2_a,1,2_b), (2_a,2_b,1), (2_b,1,2_a), (2_b,2_a,1).
		

Crossrefs

Programs

  • PARI
    colr(x,y)={my(r=y-x+1, v=[x..y], z = vector(r*(r+(1+(x-1)*2))/2), k=1); for(i=1,#v,for(j=1,v[i],z[k]=v[i]; k++)); return(z)}
    C_x(s,N)={my(x='x+O('x^N), g=if(#s <1,1, sum(i=1,#s, C_x(s[^i],N+1) * x^(s[i]) )/(1-sum(i=1,#s, x^(s[i]))))); return(g)}
    B_x(N)={my(x='x+O('x^N), h=0); for(u=1,N, my(j=0); while(vecsum(colr(u,u+j)) <= N, h += C_x(colr(u,u+j),N+1); j++)); my(a = Vec(h)); vector(N, i, a[i])}
    B_x(20)

A356737 Number of integer partitions of n into odd parts covering an interval of odd numbers.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 3, 4, 4, 6, 6, 7, 8, 9, 10, 13, 13, 15, 17, 19, 21, 25, 26, 29, 33, 37, 40, 46, 49, 54, 61, 66, 72, 81, 87, 97, 106, 115, 125, 139, 150, 163, 179, 193, 210, 232, 248, 269, 293, 317, 343, 373, 401, 433, 470, 507, 545, 590, 633, 682, 737, 790
Offset: 0

Views

Author

Gus Wiseman, Sep 03 2022

Keywords

Examples

			The a(1) = 1 through a(9) = 6 partitions:
  1  11  3    31    5      33      7        53        9
         111  1111  311    3111    331      3311      333
                    11111  111111  31111    311111    531
                                   1111111  11111111  33111
                                                      3111111
                                                      111111111
		

Crossrefs

The strict case is A034178, for compositions A332032.
The initial case is A053251, ranked by A356232 and A356603.
The initial case for compositions is A356604.
The version for compositions is A356605, ranked by A060142 /\ A356841.
A000041 counts partitions, compositions A011782.
A066208 lists numbers with all odd prime indices, counted by A000009.
A073491 lists gapless numbers, initial A055932.

Programs

  • Mathematica
    nogapQ[m_]:=Or[m=={},Union[m]==Range[Min[m],Max[m]]];
    Table[Length[Select[IntegerPartitions[n],And@@OddQ/@#&&nogapQ[(#+1)/2]&]],{n,0,30}]
Previous Showing 11-20 of 23 results. Next