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 1-9 of 9 results.

A276427 Irregular triangle read by rows: T(n,k) = number of partitions of n having k distinct parts i of multiplicity i; 0 <= k <= A328806(n)-1 = largest index of a nonzero value; n >= 0.

Original entry on oeis.org

1, 0, 1, 2, 2, 1, 3, 2, 5, 1, 1, 8, 3, 9, 6, 16, 5, 1, 19, 10, 1, 29, 11, 2, 36, 18, 2, 53, 21, 3, 65, 32, 4, 92, 38, 4, 1, 115, 54, 7, 154, 67, 10, 195, 88, 14, 257, 112, 15, 1, 318, 152, 19, 1, 419, 178, 29, 1, 516, 243, 31, 2, 663, 293, 44, 2, 821, 376, 56, 2, 1039, 465, 67, 4, 1277, 589, 89, 3, 1606, 715, 108, 7
Offset: 0

Views

Author

Emeric Deutsch, Sep 19 2016

Keywords

Comments

The sum of entries in row n is A000041(n): the partition numbers. [This allows us to know the row length, i.e., when the largest value of k is reached for which T(n,k) is nonzero. The row lengths are now listed as A328806. - M. F. Hasler, Oct 28 2019]

Examples

			Triangle starts:
1;       (n=0: partition [] has k=0 parts i of multiplicity i: T(0,0) = 1.)
0, 1;    (n=1: partition [1] has k=1 part i of multiplicity i: T(1,1) = 1.)
2;       (n=2: partitions [1,1] and [2] have k=0 parts i occurring i times.)
2, 1;    (n=3: [1,1,1] and [3] have 0, [1,2] has 1 part i occurring i times)
3, 2;    (n=4: [4], [1,1,2] and [1,1,1,1] for k=0; [1,3] & [2,2] for k=1.)
5, 1, 1; (n=5: [1,4] has i=1, [1,2,2] has i=1 and i=2 occurring i times.)
(...)
The partition [1,2,3,3,3,4] has 2 parts i of multiplicity i: i=1 and i=3.
T(14,3) = 1, since [1,2,2,3,3,3] is the only partition of 14 having k=3 parts i with multiplicity i, namely i = 1, 2 and 3.
T(14,2) = 4, counting [1,2,2,3,6], [1,2,2,4,5], [1,2,2,9] (with i=1 and i=2), and [1,3,3,3,4] (with i=1 and i=3).
		

Crossrefs

Cf. A000041 (row sums), A276428, A276429, A328806 (row lengths).

Programs

  • Maple
    G := mul((t-1)*x^(i^2)+1/(1-x^i), i = 1 .. 100): Gser := simplify(series(G, x = 0, 35)): for n from 0 to 30 do P[n] := sort(coeff(Gser, x, n)) end do: for n from 0 to 30 do seq(coeff(P[n], t, k), k = 0 .. degree(P[n])) end do; # yields sequence in triangular form
    # second Maple program:
    b:= proc(n, i) option remember; expand(
          `if`(n=0, 1, `if`(i<1, 0, add(
          `if`(i=j, x, 1)*b(n-i*j, i-1), j=0..n/i))))
        end:
    T:= n->(p->seq(coeff(p, x, i), i=0..degree(p)))(b(n$2)):
    seq(T(n), n=0..30);  # Alois P. Heinz, Sep 19 2016
  • Mathematica
    b[n_, i_] := b[n, i] = Expand[If[n==0, 1, If[i<1, 0, Sum[If[i==j, x, 1] * b[n-i*j, i-1], {j, 0, n/i}]]]]; T[n_] := Function[p, Table[ Coefficient[ p, x, i], {i, 0, Exponent[p, x]}]][b[n, n]]; Table[T[n], {n, 0, 30}] // Flatten (* Jean-François Alcover, Oct 20 2016, after Alois P. Heinz *)
  • PARI
    apply( A276427_row(n, r=List(0))={forpart(p=n, my(s, c=1); for(i=1, #p, p[i]==if(i<#p, p[i+1]) && c++ && next; c==p[i] && s++; c=1); while(#r<=s, listput(r,0)); r[s+1]++);Vec(r)}, [0..20]) \\ M. F. Hasler, Oct 27 2019

Formula

G.f.: G(t,x) = Product_{i>=1} ((t-1)*x^{i^2} + 1/(1-x^i)).
T(n,0) = A276429(n).
Sum(k*T(n,k), k>=0) = A276428(n).

Extensions

Name edited by M. F. Hasler, Oct 27 2019

A276434 Sum over all partitions of n of the number of distinct parts i of multiplicity i+1.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 3, 3, 5, 6, 10, 12, 19, 23, 34, 41, 58, 72, 98, 121, 162, 200, 262, 323, 415, 511, 650, 796, 1000, 1222, 1522, 1851, 2287, 2771, 3399, 4103, 5000, 6015, 7289, 8735, 10530, 12579, 15094, 17968, 21468, 25477, 30319, 35873, 42531, 50177, 59291
Offset: 0

Views

Author

Emeric Deutsch, Sep 30 2016

Keywords

Examples

			a(6) = 3 because in the partitions [1,1,1,1,1,1], [1,1,1,1,2], [1',1,2,2], [2',2,2], [1,1,1,3], [1,2,3], [3,3], [1',1,4], [2,4], [1,5], [6] of 6 only the marked parts satisfy the requirement.
		

Crossrefs

Programs

  • Maple
    g := (sum(x^(i*(i+1))*(1-x^i), i = 1 .. 200))/(product(1-x^i, i = 1 .. 200)): gser := series(g, x = 0, 53): seq(coeff(gser, x, n), n = 0 .. 50);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0],
         `if`(i<1, 0, add((p-> p+`if`(i+1<>j, 0,
          [0, p[1]]))(b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..60);  # Alois P. Heinz, Sep 30 2016
  • Mathematica
    max = 60; s = Sum[x^(i*(i+1))*(1-x^i), {i, 1, max}]/QPochhammer[x] + O[x]^max; CoefficientList[s, x] (* Jean-François Alcover, Dec 08 2016 *)

Formula

a(n) = Sum(k*A276433(n,k), k>=0).
G.f.: g(x) = Sum_(i>=1) (x^(i(i+1))(1-x^i))/Product_(i>=1) (1-x^i).

A277101 Sum over all partitions of n of the number of distinct parts i of multiplicity i - 1.

Original entry on oeis.org

0, 0, 1, 1, 1, 2, 4, 5, 8, 10, 15, 20, 29, 37, 52, 67, 89, 115, 152, 192, 251, 316, 405, 508, 644, 799, 1006, 1243, 1546, 1901, 2351, 2871, 3527, 4289, 5232, 6336, 7688, 9264, 11189, 13430, 16137, 19299, 23097, 27514, 32799, 38944, 46246, 54738, 64782, 76430, 90171
Offset: 0

Views

Author

Emeric Deutsch, Oct 10 2016

Keywords

Examples

			a(6) = 4 because in the partitions [1,1,1,1,1,1], [1,1,1,1,2'], [1,1,2,2], [2,2,2], [1,1,1,3], [1,2',3], [3',3], [1,1,4], [2',4], [1,5], [6] of 6 only the marked parts satisfy the requirement.
		

Crossrefs

Programs

  • Maple
    g := (sum(x^(i*(i+1))*(1-x^(i+1)), i = 1 .. 200))/(product(1-x^i, i = 1 .. 200)): gser := series(g, x = 0, 53): seq(coeff(gser, x, n), n = 0 .. 50);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0],
         `if`(i<1, 0, add((p-> p+`if`(i-1<>j, 0,
          [0, p[1]]))(b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..60);  # Alois P. Heinz, Oct 10 2016
  • Mathematica
    max = 60; s = Sum[x^(i*(i+1))*(1-x^(1+i)), {i, 1, max}]/QPochhammer[x] + O[x]^max; CoefficientList[s, x] (* Jean-François Alcover, Dec 08 2016 *)

Formula

a(n) = Sum(k*A277100(n,k), k>=0).
G.f.: g(x) = Sum_(i>=1)(x^(i(i+1))(1-x^(i+1)))/Product_(i>=1)(1-x^i).

A276433 Irregular triangle read by rows: T(n,k) is the number of partitions of n having k distinct parts i of multiplicity i+1 (n>=0).

Original entry on oeis.org

1, 1, 1, 1, 3, 4, 1, 6, 1, 8, 3, 12, 3, 18, 3, 1, 24, 6, 32, 10, 45, 10, 1, 59, 17, 1, 79, 21, 1, 104, 28, 3, 137, 37, 2, 177, 50, 4, 229, 64, 4, 295, 82, 8, 377, 105, 8, 477, 139, 10, 1, 605, 174, 13, 761, 220, 21, 956, 275, 24, 1193, 350, 31, 1
Offset: 0

Views

Author

Emeric Deutsch, Sep 30 2016

Keywords

Comments

Sum of entries in row n is A000041(n) (the partition numbers).
T(n,0) = A277099(n).
Sum(k*T(n,k), k>=0) = A276434(n).

Examples

			The partition [1,1,3,3,3,3,4] has 2 parts i of multiplicity i+1: 1 and 3.
T(5,1) = 1, counting [1,1,3].
T(6,1) = 3, counting [1,1,4], [1,1,2,2], and [2,2,2].
T(8,2) = 1, counting [1,1,2,2,2].
Triangle starts:
1;
1;
1,1;
3;
4,1;
6,1;
8,3.
		

Crossrefs

Programs

  • Maple
    G := mul((t-1)*x^(i*(i+1))+1/(1-x^i), i = 1 .. 100): Gser := simplify(series(G, x = 0, 35)): for n from 0 to 30 do P[n] := sort(coeff(Gser, x, n)) end do: for n from 0 to 30 do seq(coeff(P[n],t,k),k = 0 .. degree(P[n])) end do; # yields sequence in triangular form
    # second Maple program:
    b:= proc(n, i) option remember; expand(
          `if`(n=0, 1, `if`(i<1, 0, add(
          `if`(i+1=j, x, 1)*b(n-i*j, i-1), j=0..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n$2)):
    seq(T(n), n=0..30);  # Alois P. Heinz, Sep 30 2016
  • Mathematica
    b[n_, i_] := b[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, Sum[If[i + 1 == j, x, 1]*b[n - i*j, i - 1], {j, 0, n/i}]]]]; T[n_] := Function[p, Table[ Coefficient[p, x, i], {i, 0, Exponent[p, x]}]][b[n, n]]; Table[T[n], {n, 0, 30}] // Flatten (* Jean-François Alcover, Nov 28 2016 after Alois P. Heinz *)

Formula

G.f.: G(t,x) = Product_{i>=1} ((t-1)*x^(i(i+1)) + 1/(1-x^i)).

A277099 Number of partitions of n containing no part i of multiplicity i+1.

Original entry on oeis.org

1, 1, 1, 3, 4, 6, 8, 12, 18, 24, 32, 45, 59, 79, 104, 137, 177, 229, 295, 377, 477, 605, 761, 956, 1193, 1484, 1840, 2276, 2800, 3441, 4210, 5141, 6261, 7603, 9206, 11132, 13419, 16144, 19380, 23223, 27763, 33134, 39467, 46931, 55703, 66008, 78085, 92239, 108776, 128091, 150617
Offset: 0

Views

Author

Emeric Deutsch, Sep 30 2016

Keywords

Examples

			a(4) = 4 because we have [1,1,1,1], [1,3], [2,2], and [4]; the partition [1,1,2] does not qualify.
		

Crossrefs

Programs

  • Maple
    g:= product(1/(1-x^i)-x^(i*(i+1)), i = 1 .. 100): gser := series(g, x = 0, 53): seq(coeff(gser, x, n), n = 0 .. 50);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(`if`(i+1=j, 0, b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..60);  # Alois P. Heinz, Sep 30 2016
  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1/(1-x^k) - x^(k*(k+1))), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Sep 30 2016 *)

Formula

a(n) = A276433(n,0).
G.f.: g(x) = Product_{i>=1} (1/(1-x^i) - x^(i*(i+1))).

A277100 Irregular triangle read by rows: T(n,k) is the number of partitions of n having k distinct parts i (i>=2) of multiplicity i-1 (n>=0).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 4, 1, 5, 2, 7, 4, 10, 5, 15, 6, 1, 21, 8, 1, 28, 13, 1, 37, 18, 1, 50, 25, 2, 67, 31, 3, 88, 42, 5, 115, 55, 6, 150, 73, 8, 193, 93, 11, 248, 122, 15, 317, 154, 19, 402, 200, 24, 1, 508, 253, 30, 1, 640, 320, 41, 1, 802, 399, 53, 1, 1002, 503, 69, 1
Offset: 0

Views

Author

Emeric Deutsch, Oct 10 2016

Keywords

Comments

Sum of entries in row n is A000041(n) (the partition numbers).
T(n,0) = A277102(n).
Sum(k*T(n,k), k>=0) = A277101(n).

Examples

			The partition [1,1,2,3,3,3,3,4,4,4] has 2 parts i of multiplicity i-1: 2 and 4.
T(5,1) = 2, counting [1,1,1,2] and [2,3].
T(8,2) = 1, counting [2,3,3].
Triangle starts:
1;
1;
1, 1;
2, 1;
4, 1;
5, 2;
7, 4;
...
		

Crossrefs

Programs

  • Maple
    g := mul((t-1)*x^(i*(i+1))+1/(1-x^(i+1)), i = 1 .. 100)/(1-x): gser := simplify(series(g, x = 0, 35)): for n from 0 to 30 do P[n] := sort(coeff(gser, x, n)) end do: for n from 0 to 30 do seq(coeff(P[n], t, k), k = 0 .. degree(P[n])) end do; # yields sequence in triangular form
    # second Maple program:
    b:= proc(n, i) option remember; expand(
          `if`(n=0, 1, `if`(i<1, 0, add(
          `if`(i-1=j, x, 1)*b(n-i*j, i-1), j=0..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n$2)):
    seq(T(n), n=0..30);  # Alois P. Heinz, Oct 10 2016
  • Mathematica
    b[n_, i_] := b[n, i] = Expand[If[n==0, 1, If[i<1, 0, Sum[If[i-1 == j, x, 1]*b[n-i*j, i-1], {j, 0, n/i}]]]]; T[n_] := Function[p, Table[ Coefficient[p, x, i], {i, 0, Exponent[p, x]}]][b[n, n]]; Table[T[n], {n, 0, 30}] // Flatten (* Jean-François Alcover, Dec 08 2016 after Alois P. Heinz *)

Formula

G.f.: G(t,x) = Product_{i>=1} ((t-1)*x^(i(i+1)) + 1/(1-x^(i+1))).

A277102 Number of partitions of n containing no part i of multiplicity i-1.

Original entry on oeis.org

1, 1, 1, 2, 4, 5, 7, 10, 15, 21, 28, 37, 50, 67, 88, 115, 150, 193, 248, 317, 402, 508, 640, 802, 1002, 1248, 1545, 1908, 2351, 2887, 3532, 4313, 5251, 6377, 7724, 9334, 11254, 13541, 16253, 19473, 23286, 27791, 33100, 39362, 46723, 55370, 65504, 77377, 91257, 107477, 126380
Offset: 0

Views

Author

Emeric Deutsch, Oct 10 2016

Keywords

Examples

			a(4) = 4 because we have [1,1,1,1], [1,3], [2,2], and [4]; the partition [1,1,2] does not qualify.
		

Crossrefs

Programs

  • Maple
    g := (product(1/(1-x^(i+1))-x^(i*(i+1)), i = 1 .. 100))/(1-x): gser := series(g, x = 0, 53): seq(coeff(gser, x, n), n = 0 .. 50);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(`if`(i-1=j, 0, b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..60);  # Alois P. Heinz, Oct 10 2016
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0, 1, If[i<1, 0, Sum[If[i-1 == j, 0, b[n-i*j, i-1]], {j, 0, n/i}]]]; a[n_] := b[n, n]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Dec 11 2016 after Alois P. Heinz *)

Formula

a(n) = A277100(n,0).
G.f.: g(x) = Product_{i>=1}(1/(1-x^(i+1)) - x^(i(i+1))).

A328806 Row lengths of A276427: largest k such that a partition of n has k-1 distinct parts i of multiplicity i.

Original entry on oeis.org

1, 2, 1, 2, 2, 3, 2, 2, 3, 3, 3, 3, 3, 3, 4, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7
Offset: 0

Views

Author

M. F. Hasler, Oct 27 2019

Keywords

Comments

Columns of A276427 are numbered starting with 0, so the row length is one more than the index of the last column.

Examples

			For n = 0, the empty partition [] has 0 parts i with multiplicity i, so a(0) = 1.
For n = 1, the partition [1] has one part i with multiplicity i, whence a(1) = 2.
For n = 2, both partitions [1,1] and [2] have 0 parts i with multiplicity i, so a(2) = 1.
For n = 3, the partition [1,2] has one part i with multiplicity i, hence a(3) = 2.
For n = 4, the partitions [1,3] and [2,2] have one part i with multiplicity i, so a(4) = 2.
For n = 5, the partition [1,2,2] has 2 parts i with multiplicity i, hence a(5) = 3.
The smallest partition with k-1 = 3 parts i with multiplicity i is [1,2,2,3,3,3], for n = 14, whence a(14) = 4.
		

Crossrefs

Programs

Extensions

More terms from Alois P. Heinz, Oct 28 2019

A328891 Irregular table T(n,k) = #{m > 0: m occurs m times in the k-th partition of n, using A&S order (A036036)}, 1 <= k <= A000041(n), n >= 0.

Original entry on oeis.org

0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 2, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1
Offset: 0

Views

Author

M. F. Hasler, Oct 29 2019

Keywords

Comments

In the n-th row, the partitions of n are considered in the "Abramowitz and Stegun" or graded (reflected or not) colexicographic ordering, as in A036036 or A036037. For each partition this counts the numbers m > 0 such that there are exactly m parts equal to m in the partition.
Row lengths are A000041(n) = number of partitions of n, the partition numbers.

Examples

			The table reads:
  n \ T(n,k), ...
  0 : 0;   (The only partition of 0 is [], having no number at all in it.)
  1 : 1;   (The only partition of 1 is [1], in which the number m=1 occurs 1 time.)
  2 : 0,0;   (Neither [2] nor [1,1] have some m occurring m times.)
  3 : 0,1,0;   ([3] and [1,1,1] have no m, but [1,2] has m=1 occurring m times.)
  4 : 0,1,1,0,0;   (Here [1,3] and [2,2] have m=1 resp. m=2 occurring m times.)
  5 : 0,1,0,0,2,0,0;   ([1,4] has m=1, [1,2,2] has m=1 and m=2 occurring m times.)
  6 : 0,1,0,0,0,1,0,0,1,0,0;
  7 : 0,1,0,0,0,1,1,1,0,0,1,0,1,0,0;
  (...)
Column 1 = (0,1,0,...) = A063524, characteristic function of {1}: The corresponding partition is [n], except for [] when n=0.
Column 2 = (0,1,1,1,...) = signum(n-2) = A057427(n-2), n >= 2: The corresponding partition is [1, n-1].
Column 3 = A063524(n-3) = A185014(n), characteristic function of {4}: The corresponding partition is [2, n-2] for n >= 4, and [1,1,1] for n = 3.
Column 4 = (0,...) = A000004(n-4), the zero function: The corresponding partition is [3, n-3] for n >= 6, and [1,1,2] for n = 4 and [1,1,3] for n = 5.
Row sums = A276428(n) = sum over all partitions of n of the number of distinct parts m of multiplicity m.
		

Crossrefs

Cf. A036036 (list of partitions in Abramowitz & Stegun or graded reflected colexicographic order).
Cf. A000041 (partition numbers = row lengths).
Cf. A063524 (col.1: chi_{1}), A057427 (col.2: signum), A185014 (col.3: chi_{4}), A000004 (col.4: zero).
Cf. A276427 (frequency of 0, ..., max.value in each row), A276428 (row sums), A276429, A276434, A277101.
Cf. A328806 (row length of A276427(n) = 1 + largest value in row n).

Programs

  • PARI
    apply( A328891_row(n, r=[])={forpart(p=n, my(s, c=1); for(i=1, #p, p[i]==if(i<#p, p[i+1]) && c++ && next; c==p[i] && s++; c=1); r=concat(r,s));r}, [0..12])
Showing 1-9 of 9 results.