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 1-8 of 8 results.

A032020 Number of compositions (ordered partitions) of n into distinct parts.

Original entry on oeis.org

1, 1, 1, 3, 3, 5, 11, 13, 19, 27, 57, 65, 101, 133, 193, 351, 435, 617, 851, 1177, 1555, 2751, 3297, 4757, 6293, 8761, 11305, 15603, 24315, 30461, 41867, 55741, 74875, 98043, 130809, 168425, 257405, 315973, 431065, 558327, 751491, 958265, 1277867, 1621273
Offset: 0

Views

Author

Christian G. Bower, Apr 01 1998

Keywords

Comments

Compositions into distinct parts are equivalent to (1,1)-avoiding compositions. - Gus Wiseman, Jun 25 2020
All terms are odd. - Alois P. Heinz, Apr 09 2021

Examples

			a(6) = 11 because 6 = 5+1 = 4+2 = 3+2+1 = 3+1+2 = 2+4 = 2+3+1 = 2+1+3 = 1+5 = 1+3+2 = 1+2+3.
From _Gus Wiseman_, Jun 25 2020: (Start)
The a(0) = 1 through a(7) = 13 strict compositions:
  ()  (1)  (2)  (3)    (4)    (5)    (6)      (7)
                (1,2)  (1,3)  (1,4)  (1,5)    (1,6)
                (2,1)  (3,1)  (2,3)  (2,4)    (2,5)
                              (3,2)  (4,2)    (3,4)
                              (4,1)  (5,1)    (4,3)
                                     (1,2,3)  (5,2)
                                     (1,3,2)  (6,1)
                                     (2,1,3)  (1,2,4)
                                     (2,3,1)  (1,4,2)
                                     (3,1,2)  (2,1,4)
                                     (3,2,1)  (2,4,1)
                                              (4,1,2)
                                              (4,2,1)
(End)
		

References

  • Mohammad K. Azarian, A Generalization of the Climbing Stairs Problem II, Missouri Journal of Mathematical Sciences, Vol. 16, No. 1, Winter 2004, pp. 12-17.

Crossrefs

Row sums of A241719.
Main diagonal of A261960.
Dominated by A003242 (anti-run compositions).
These compositions are ranked by A233564.
(1,1)-avoiding patterns are counted by A000142.
Numbers with strict prime signature are A130091.
(1,1,1)-avoiding compositions are counted by A232432.
(1,1)-matching compositions are counted by A261982.
Inseparable partitions are counted by A325535.
Patterns matched by compositions are counted by A335456.
Strict permutations of prime indices are counted by A335489.

Programs

  • Maple
    b:= proc(n, i) b(n, i):= `if`(n=0, [1], `if`(i<1, [], zip((x, y)
          -> x+y, b(n, i-1), `if`(i>n, [], [0, b(n-i, i-1)[]]), 0))) end:
    a:= proc(n) local l; l:=b(n, n): add((i-1)! *l[i], i=1..nops(l)) end:
    seq(a(n), n=0..50);  # Alois P. Heinz, Dec 12 2012
    # second Maple program:
    T:= proc(n, k) option remember; `if`(k<0 or n<0, 0,
          `if`(k=0, `if`(n=0, 1, 0), T(n-k, k) +k*T(n-k, k-1)))
        end:
    a:= n-> add(T(n, k), k=0..floor((sqrt(8*n+1)-1)/2)):
    seq(a(n), n=0..60);  # Alois P. Heinz, Sep 04 2015
  • Mathematica
    f[list_]:=Length[list]!; Table[Total[Map[f, Select[IntegerPartitions[n], Sort[#] == Union[#] &]]], {n, 0,30}]
    T[n_, k_] := T[n, k] = If[k<0 || n<0, 0, If[k==0, If[n==0, 1, 0], T[n-k, k] + k*T[n-k, k-1]]]; a[n_] := Sum[T[n, k], {k, 0, Floor[(Sqrt[8*n + 1] - 1) / 2]}]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Sep 22 2015, after Alois P. Heinz *)
  • PARI
    N=66;  q='q+O('q^N);
    gf=sum(n=0,N, n!*q^(n*(n+1)/2) / prod(k=1,n, 1-q^k ) );
    Vec(gf)
    /* Joerg Arndt, Oct 20 2012 */
    
  • PARI
    Q(N) = { \\ A008289
      my(q = vector(N)); q[1] = [1, 0, 0, 0];
      for (n = 2, N,
        my(m = (sqrtint(8*n+1) - 1)\2);
        q[n] = vector((1 + (m>>2)) << 2); q[n][1] = 1;
        for (k = 2, m, q[n][k] = q[n-k][k] + q[n-k][k-1]));
      return(q);
    };
    seq(N) = concat(1, apply(q -> sum(k = 1, #q, q[k] * k!), Q(N)));
    seq(43) \\ Gheorghe Coserea, Sep 09 2018

Formula

"AGK" (ordered, elements, unlabeled) transform of 1, 1, 1, 1, ...
G.f.: Sum_{k>=0} k! * x^((k^2+k)/2) / Product_{j=1..k} (1-x^j). - David W. Wilson May 04 2000
a(n) = Sum_{m=1..n} A008289(n,m)*m!. - Geoffrey Critzer, Sep 07 2012

A327245 Number T(n,k) of colored compositions of n using all colors of a k-set such that all parts have different color patterns and the patterns for parts i have i colors in (weakly) increasing order; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 3, 0, 3, 10, 13, 0, 3, 39, 87, 75, 0, 5, 100, 510, 836, 541, 0, 11, 303, 2272, 7042, 9025, 4683, 0, 13, 782, 9999, 46628, 104255, 109110, 47293, 0, 19, 2009, 39369, 284319, 948725, 1662273, 1466003, 545835, 0, 27, 5388, 154038, 1577256, 7676830, 19798096, 28538496, 21713032, 7087261
Offset: 0

Views

Author

Alois P. Heinz, Sep 14 2019

Keywords

Examples

			T(3,1) = 3: 3aaa, 2aa1a, 1a2aa.
T(3,2) = 10: 3aab, 3abb, 2aa1b, 2ab1a, 2ab1b, 2bb1a, 1a2ab, 1a2bb, 1b2aa, 1b2ab.
T(3,3) = 13: 3abc, 2ab1c, 2ac1b, 2bc1a, 1a2bc, 1b2ac, 1c2ab, 1a1b1c, 1a1c1b, 1b1a1c, 1b1c1a, 1c1a1b, 1c1b1a.
Triangle T(n,k) begins:
  1;
  0,  1;
  0,  1,    3;
  0,  3,   10,    13;
  0,  3,   39,    87,     75;
  0,  5,  100,   510,    836,    541;
  0, 11,  303,  2272,   7042,   9025,    4683;
  0, 13,  782,  9999,  46628, 104255,  109110,   47293;
  0, 19, 2009, 39369, 284319, 948725, 1662273, 1466003, 545835;
  ...
		

Crossrefs

Columns k=0-2 give: A000007, A032020 (for n>0), A327847.
Main diagonal gives A000670.
Row sums give A321586.
T(2n,n) gives A327589.

Programs

  • Maple
    C:= binomial:
    b:= proc(n, i, k, p) option remember; `if`(n=0, p!, `if`(i<1, 0, add(
          b(n-i*j, min(n-i*j, i-1), k, p+j)*C(C(k+i-1, i), j), j=0..n/i)))
        end:
    T:= (n, k)-> add(b(n$2, i, 0)*(-1)^(k-i)*C(k, i), i=0..k):
    seq(seq(T(n, k), k=0..n), n=0..10);
  • Mathematica
    c = Binomial;
    b[n_, i_, k_, p_] := b[n, i, k, p] = If[n == 0, p!, If[i < 1, 0, Sum[b[n - i*j, Min[n - i*j, i-1], k, p + j] c[c[k + i - 1, i], j], {j, 0, n/i}]]];
    T[n_, k_] := Sum[b[n, n, i, 0] (-1)^(k - i) c[k, i], {i, 0, k}];
    Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Apr 29 2020, after Alois P. Heinz *)

Formula

Sum_{k=1..n} k * T(n,k) = A327588(n).

A120774 Number of ordered set partitions of [n] where equal-sized blocks are ordered with increasing least elements.

Original entry on oeis.org

1, 1, 2, 8, 31, 147, 899, 5777, 41024, 322488, 2749325, 25118777, 245389896, 2554780438, 28009868787, 323746545433, 3933023224691, 49924332801387, 661988844566017, 9138403573970063, 131043199040556235, 1949750421507432009, 30031656711776544610
Offset: 0

Views

Author

Alford Arnold, Jul 12 2006

Keywords

Comments

Old name was: Row sums of A179233.
a(n) is the number of ways to linearly order the blocks in each set partition of {1,2,...,n} where two blocks are considered identical if they have the same number of elements. - Geoffrey Critzer, Sep 29 2011

Examples

			A179233 begins 1; 1; 1 1; 6 1 1; 8 3 18 1 1 ... with row sums 1, 1 2 8 31 147 ...
a(3) = 8: 123, 1|23, 23|1, 2|13, 13|2, 3|12, 12|3, 1|2|3. - _Alois P. Heinz_, Apr 27 2017
		

Crossrefs

Row sums of A179233, A285824.
Main diagonal of A327244.

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(n=0 or i=1,
          (p+n)!/n!, add(b(n-i*j, i-1, p+j)*combinat
          [multinomial](n, n-i*j, i$j)/j!^2, j=0..n/i))
        end:
    a:= n-> b(n$2, 0):
    seq(a(n), n=0..25);  # Alois P. Heinz, Apr 27 2017
  • Mathematica
    f[{x_,y_}]:= x!^y y!;   Table[Total[Table[n!,{PartitionsP[n]}]/Apply[Times,Map[f,Map[Tally,Partitions[n]],{2}],2] * Apply[Multinomial,Map[Last,Map[Tally,Partitions[n]],{2}],2]],{n,0,20}]  (* Geoffrey Critzer, Sep 29 2011 *)

Extensions

Leading 1 inserted, definition simplified by R. J. Mathar, Sep 28 2011
a(15) corrected, more terms, and new name (using Geoffrey Critzer's comment) from Alois P. Heinz, Apr 27 2017

A327673 Number T(n,k) of colored compositions of n using all colors of a k-set such that all parts have different color patterns and the patterns for parts i are sorted and have i colors (in arbitrary order); triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 3, 0, 3, 18, 19, 0, 3, 60, 171, 121, 0, 5, 210, 1173, 1996, 1041, 0, 11, 798, 7512, 22784, 27225, 11191, 0, 13, 2462, 39708, 196904, 411115, 382086, 130663, 0, 19, 7891, 204987, 1546042, 4991815, 7843848, 5932843, 1731969
Offset: 0

Views

Author

Alois P. Heinz, Sep 21 2019

Keywords

Examples

			T(3,1) = 3: 3aaa, 2aa1a, 1a2aa.
T(3,2) = 18: 3aab, 3aba, 3baa, 3abb, 3bab, 3bba, 2aa1b, 2ab1a, 2ba1a, 2ab1b, 2ba1b, 2bb1a, 1a2ab, 1a2ba, 1a2bb, 1b2aa, 1b2ab, 1b2ba.
T(3,3) = 19: 3abc, 3acb, 3bac, 3bca, 3cab, 3cba, 2ab1c, 2ac1b, 2ba1c, 2bc1a, 2ca1b, 2cb1a, 1a2bc, 1a2cb, 1b2ac, 1b2ca, 1c2ab, 1c2ba, 1a1b1c.
Triangle T(n,k) begins:
  1;
  0,  1;
  0,  1,    3;
  0,  3,   18,    19;
  0,  3,   60,   171,    121;
  0,  5,  210,  1173,   1996,   1041;
  0, 11,  798,  7512,  22784,  27225,  11191;
  0, 13, 2462, 39708, 196904, 411115, 382086, 130663;
  ...
		

Crossrefs

Columns k=0-2 give: A000007, A032020 (for n>0), A327768.
Main diagonal gives A327674.
Row sums give A327675.
T(2n,n) gives A327678.

Programs

  • Maple
    b:= proc(n, i, k, p) option remember;
         `if`(n=0, p!, `if`(i<1, 0, add(binomial(k^i, j)*
          b(n-i*j, min(n-i*j, i-1), k, p+j)/j!, j=0..n/i)))
        end:
    T:= (n, k)-> add(b(n$2, i, 0)*(-1)^(k-i)*binomial(k, i), i=0..k):
    seq(seq(T(n, k), k=0..n), n=0..10);
  • Mathematica
    b[n_, i_, k_, p_] := b[n, i, k, p] = If[n==0, p!, If[i<1, 0, Sum[Binomial[ k^i, j] b[n - i j, Min[n - i j, i - 1], k, p + j]/j!, {j, 0, n/i}]]];
    T[n_, k_] := Sum[b[n, n, i, 0] (-1)^(k - i) Binomial[k, i], {i, 0, k}];
    Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, May 30 2020, after Maple *)

Formula

Sum_{k=1..n} k * T(n,k) = A327676(n).

A309670 Number of colored compositions of n using all colors of an initial interval of the color palette such that all parts have different color patterns and the patterns for parts i are sorted and have i colors in (weakly) increasing order.

Original entry on oeis.org

1, 1, 3, 21, 115, 813, 7627, 71173, 740023, 8544169, 107195083, 1434581205, 20499413667, 312262663989, 4992164670007, 84221279919193, 1492818584618099, 27607818180267269, 533522844488072987, 10724970103003953053, 223859943086157531063, 4847766598150865273721
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2019

Keywords

Crossrefs

Row sums of A327244.

Programs

  • Maple
    C:= binomial:
    b:= proc(n, i, k, p) option remember; `if`(n=0, p!, `if`(i<1, 0, add(
          b(n-i*j, min(n-i*j, i-1), k, p+j)/j!*C(C(k+i-1, i), j), j=0..n/i)))
        end:
    a:= n-> add(add(b(n$2, i, 0)*(-1)^(k-i)*C(k, i), i=0..k), k=0..n):
    seq(a(n), n=0..23);
  • Mathematica
    c = Binomial;
    b[n_, i_, k_, p_] := b[n, i, k, p] = If[n == 0, p!, If[i<1, 0, Sum[b[n - i*j, Min[n - i*j, i-1], k, p+j]/j!*c[c[k+i-1, i], j], {j, 0, n/i}]]];
    a[n_] := Sum[Sum[b[n, n, i, 0]*(-1)^(k-i)*c[k, i], {i, 0, k}], {k, 0, n}];
    Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Mar 05 2022, after Alois P. Heinz *)

A327595 Total number of colors in all colored compositions of n using all colors of an initial interval of the color palette such that all parts have different color patterns and the patterns for parts i are sorted and have i colors in (weakly) increasing order.

Original entry on oeis.org

0, 1, 5, 47, 343, 2989, 33185, 360963, 4279363, 55461897, 771543693, 11345355815, 176710558327, 2913914537349, 50149603855065, 906096874764227, 17125269159665511, 336432862441344121, 6882511824853124773, 146018382159954093023, 3207861915702573763355
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2019

Keywords

Crossrefs

Cf. A327244.

Programs

  • Maple
    C:= binomial:
    b:= proc(n, i, k, p) option remember; `if`(n=0, p!, `if`(i<1, 0, add(
          b(n-i*j, min(n-i*j, i-1), k, p+j)/j!*C(C(k+i-1, i), j), j=0..n/i)))
        end:
    a:= n-> add(add(k*b(n$2, i, 0)*(-1)^(k-i)*C(k, i), i=0..k), k=0..n):
    seq(a(n), n=0..21);
  • Mathematica
    c = Binomial;
    b[n_, i_, k_, p_] := b[n, i, k, p] = If[n == 0, p!, If[i < 1, 0, Sum[
        b[n-i*j, Min[n-i*j, i-1], k, p+j]/j!*c[c[k+i-1, i], j], {j, 0, n/i}]]];
    a[n_] := Sum[Sum[k*b[n, n, i, 0]*(-1)^(k-i)*c[k, i], {i, 0, k}], {k, 0, n}];
    Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Apr 11 2022, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=1..n} k * A327244(n,k).

A327596 Number of colored compositions of 2n using all colors of an n-set such that all parts have different color patterns and the patterns for parts i are sorted and have i colors in (weakly) increasing order.

Original entry on oeis.org

1, 1, 27, 1222, 78819, 7990555, 1075539168, 185948116920, 39826324710186, 10231314625984628, 3097070454570888110, 1088018981038197792790, 436918864329884469153204, 198400793333371519398942287, 100941775818744369615731919906, 57064609834208008799145534143376
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2019

Keywords

Crossrefs

Cf. A327244.

Programs

  • Maple
    C:= binomial:
    b:= proc(n, i, k, p) option remember; `if`(n=0, p!, `if`(i<1, 0, add(
          b(n-i*j, min(n-i*j, i-1), k, p+j)/j!*C(C(k+i-1, i), j), j=0..n/i)))
        end:
    a:= n-> add(b(2*n$2, i, 0)*(-1)^(n-i)*C(n, i), i=0..n):
    seq(a(n), n=0..17);
  • Mathematica
    c = Binomial;
    b[n_, i_, k_, p_] := b[n, i, k, p] = If[n == 0, p!, If[i < 1, 0, Sum[
        b[n-i*j, Min[n-i*j, i-1], k, p+j]/j!*c[c[k+i-1, i], j], {j, 0, n/i}]]];
    a[n_] := Sum[b[2n, 2n, i, 0]*(-1)^(n-i)*c[n, i], {i, 0, n}];
    Table[a[n], {n, 0, 17}] (* Jean-François Alcover, Apr 11 2022, after Alois P. Heinz *)

Formula

a(n) = A327244(2n,n).

A327841 Number of colored compositions of n using all colors of a 2-set such that all parts have different color patterns and the patterns for parts i are sorted and have i colors in (weakly) increasing order.

Original entry on oeis.org

0, 0, 2, 10, 27, 70, 223, 508, 1193, 2822, 7048, 15690, 35072, 79018, 167667, 382976, 823599, 1742082, 3765187, 7785290, 16299074, 34337380, 70503188, 143916326, 296390373, 597048414, 1202172962, 2416614660, 4813022691, 9551780272, 18833189269, 37248671816
Offset: 0

Views

Author

Alois P. Heinz, Sep 27 2019

Keywords

Crossrefs

Column k=2 of A327244.

Programs

  • Maple
    b:= proc(n, i, k, p) option remember; `if`(n=0, p!,
          `if`(i<1, 0, add(b(n-i*j, min(n-i*j, i-1), k, p+j)/
           j!*binomial(binomial(k+i-1, i), j), j=0..n/i)))
        end:
    a:= n-> (k-> add(b(n$2, i, 0)*(-1)^(k-i)*
             binomial(k, i), i=0..k))(2):
    seq(a(n), n=0..35);
Showing 1-8 of 8 results.