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 1-10 of 13 results. Next

A015723 Number of parts in all partitions of n into distinct parts.

Original entry on oeis.org

1, 1, 3, 3, 5, 8, 10, 13, 18, 25, 30, 40, 49, 63, 80, 98, 119, 149, 179, 218, 266, 318, 380, 455, 541, 640, 760, 895, 1050, 1234, 1442, 1679, 1960, 2272, 2635, 3052, 3520, 4054, 4669, 5359, 6142, 7035, 8037, 9170, 10460, 11896, 13517, 15349, 17394, 19691
Offset: 1

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Author

Keywords

Examples

			The strict integer partitions of 6 are {(6), (5,1), (4,2), (3,2,1)} with a total of 1 + 2 + 2 + 3 = 8 parts, so a(6) = 8. - _Gus Wiseman_, May 09 2019
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<1, [0, 0],
          add((l->[l[1], l[2]+l[1]*j])(b(n-i*j, i-1)), j=0..min(n/i, 1))))
        end:
    a:= n-> b(n, n)[2]:
    seq(a(n), n=1..50);  # Alois P. Heinz, Feb 27 2013
  • Mathematica
    nn=50; Rest[CoefficientList[Series[D[Product[1+y x^i,{i,1,nn}],y]/.y->1,{x,0,nn}],x]]  (* Geoffrey Critzer, Oct 29 2012; fixed by Vaclav Kotesovec, Apr 16 2016 *)
    q[n_, k_] := q[n, k] = If[nVaclav Kotesovec, Apr 16 2016 *)
    Table[Length[Join@@Select[IntegerPartitions[n],UnsameQ@@#&]],{n,1,50}] (* Gus Wiseman, May 09 2019 *)
    b[n_, i_] := b[n, i] = If[n == 0, {1, 0}, If[i<1, {0, 0},
       Sum[{#[[1]], #[[2]] + #[[1]]*j}&@ b[n-i*j, i-1], {j, 0, Min[n/i, 1]}]]];
    a[n_] := b[n, n][[2]];
    Array[a, 50] (* Jean-François Alcover, May 21 2021, 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 */

Formula

G.f.: sum(k>=1, x^k/(1+x^k) ) * prod(m>=1, 1+x^m ). Convolution of A048272 and A000009. - Vladeta Jovovic, Nov 26 2002
G.f.: sum(k>=1, k*x^(k*(k+1)/2)/prod(i=1..k, 1-x^i ) ). - Vladeta Jovovic, Sep 21 2005
a(n) = A238131(n)+A238132(n) = sum_{k=1..n} A048272(k)*A000009(n-k). - Mircea Merca, Feb 26 2014
a(n) = Sum_{k>=1} k*A008289(n,k). - Vaclav Kotesovec, Apr 16 2016
a(n) ~ 3^(1/4) * log(2) * exp(Pi*sqrt(n/3)) / (2 * Pi * n^(1/4)). - Vaclav Kotesovec, May 19 2018
For n > 0, a(n) = A116676(n) + A116680(n). - Vaclav Kotesovec, May 26 2018

Extensions

Extended and corrected by Naohiro Nomoto, Feb 24 2002

A091602 Triangle: T(n,k) is the number of partitions of n such that some part is repeated k times and no part is repeated more than k times.

Original entry on oeis.org

1, 1, 1, 2, 0, 1, 2, 2, 0, 1, 3, 2, 1, 0, 1, 4, 3, 2, 1, 0, 1, 5, 4, 3, 1, 1, 0, 1, 6, 7, 3, 3, 1, 1, 0, 1, 8, 8, 6, 3, 2, 1, 1, 0, 1, 10, 12, 7, 5, 3, 2, 1, 1, 0, 1, 12, 15, 11, 6, 5, 2, 2, 1, 1, 0, 1, 15, 21, 14, 10, 5, 5, 2, 2, 1, 1, 0, 1, 18, 26, 20, 12, 9, 5, 4, 2, 2, 1, 1, 0, 1, 22, 35, 25, 18, 11, 8, 5, 4, 2, 2, 1, 1, 0, 1
Offset: 1

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Author

Christian G. Bower, Jan 23 2004

Keywords

Comments

From Gary W. Adamson, Mar 13 2010: (Start)
The triangle by rows = finite differences starting from the top, of an array in which row 1 = p(x)/p(x^2), row 2 = p(x)/p(x^3), ... row k = p(x)/p(x^k); such that p(x) = polcoeff A000041: (1 + x + 2x^2 + 3x^3 + 5x^4 + 7x^5 + ...)
Note that p(x)/p(x^2) = polcoeff A000009: (1 + x + x^2 + 2x^3 + 2x^4 + ...).
Refer to the example. (End)

Examples

			Triangle starts:
   1:  1;
   2:  1,  1;
   3:  2,  0,  1;
   4:  2,  2,  0,  1;
   5:  3,  2,  1,  0,  1;
   6:  4,  3,  2,  1,  0,  1;
   7:  5,  4,  3,  1,  1,  0,  1;
   8:  6,  7,  3,  3,  1,  1,  0,  1;
   9:  8,  8,  6,  3,  2,  1,  1,  0,  1;
  10: 10, 12,  7,  5,  3,  2,  1,  1,  0,  1;
  11: 12, 15, 11,  6,  5,  2,  2,  1,  1,  0,  1;
  12: 15, 21, 14, 10,  5,  5,  2,  2,  1,  1,  0,  1;
  13: 18, 26, 20, 12,  9,  5,  4,  2,  2,  1,  1,  0,  1;
  14: 22, 35, 25, 18, 11,  8,  5,  4,  2,  2,  1,  1,  0,  1;
  ...
In the partition 5+2+2+2+1+1, 2 is repeated 3 times, no part is repeated more than 3 times.
From _Gary W. Adamson_, Mar 13 2010: (Start)
First few rows of the array =
  ...
  1, 1, 1, 2, 2, 3,  4,  5,  6,  8, 10, ... = p(x)/p(x^2) = A000009
  1, 1, 2, 2, 4, 5,  7,  9, 13, 16, 22, ... = p(x)/p(x^3)
  1, 1, 2, 3, 4, 6,  9, 12, 16, 22, 29, ... = p(x)/p(x^4)
  1, 1, 2, 3, 5, 6, 10, 13, 19, 25, 34, ... = p(x)/p(x^5)
  1, 1, 2, 3, 5, 7, 10, 14, 20, 27, 37, ... = p(x)/p(x^6)
  ...
Finally, taking finite differences from the top and deleting the first "1", we obtain triangle A091602 with row sums = A000041 starting with offset 1:
  1;
  1, 1;
  2, 0, 1;
  2, 2, 0, 1;
  3, 2, 1, 0, 1;
  4, 3, 2, 1, 0, 1;
  ...
(End)
		

Crossrefs

Row sums: A000041. Inverse: A091603. Square: A091604.
Columns 1-6: A000009, A091605-A091609. Convergent of columns: A002865.
Cf. A000009. - Gary W. Adamson, Mar 13 2010
T(2n,n) gives: A232697.

Programs

  • Maple
    g:=sum(t^k*(product((1-x^((k+1)*j))/(1-x^j),j=1..50)-product((1-x^(k*j))/(1-x^j),j=1..50)),k=1..50): gser:=simplify(series(g,x=0,20)): for n from 1 to 13 do P[n]:=coeff(gser,x^n) od: for n from 1 to 13 do seq(coeff(P[n],t^j),j=1..n) od;
    # yields sequence in triangular form - Emeric Deutsch, Mar 30 2006
    b:= proc(n, i, k) option remember; `if`(n=0, 1,
          `if`(i>n, 0, add(b(n-i*j, i+1, min(k,
           iquo(n-i*j, i+1))), j=0..min(n/i, k))))
        end:
    T:= (n, k)-> b(n, 1, k) -`if`(k=0, 0, b(n, 1, k-1)):
    seq(seq(T(n, k), k=1..n), n=1..20);
    # Alois P. Heinz, Nov 27 2013
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i>n, 0, Sum[b[n-i*j, i+1, Min[k, Quotient[n-i*j, i+1]]], {j, 0, Min[n/i, k]}]]]; t[n_, k_] := b[n, 1, k] - If[k == 0, 0, b[n, 1, k-1]]; Table[t[n, k], {n, 1, 20}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jan 17 2014, after Alois P. Heinz's second Maple program *)

Formula

G.f.: G = G(t,x) = sum(k>=1, t^k*(prod(j>=1, (1-x^((k+1)*j))/(1-x^j) ) -prod(j>=1, (1-x^(k*j))/(1-x^j) ) ) ). - Emeric Deutsch, Mar 30 2006
Sum_{k=1..n} k * T(n,k) = A264397(n). - Alois P. Heinz, Nov 20 2015

A210485 Number T(n,k) of parts in all partitions of n in which no part occurs more than k times; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

0, 0, 1, 0, 1, 3, 0, 3, 3, 6, 0, 3, 8, 8, 12, 0, 5, 11, 15, 15, 20, 0, 8, 17, 24, 29, 29, 35, 0, 10, 23, 36, 41, 47, 47, 54, 0, 13, 36, 50, 65, 71, 78, 78, 86, 0, 18, 48, 75, 91, 104, 111, 119, 119, 128, 0, 25, 69, 102, 132, 150, 165, 173, 182, 182, 192
Offset: 0

Views

Author

Alois P. Heinz, Jan 23 2013

Keywords

Comments

T(n,k) is defined for n,k >= 0. The triangle contains terms with k <= n. T(n,k) = T(n,n) = A006128(n) for k >= n.
For fixed k > 0, T(n,k) ~ 3^(1/4) * log(k+1) * exp(Pi*sqrt(2*k*n/(3*(k+1)))) / (Pi * (8*k*(k+1)*n)^(1/4)). - Vaclav Kotesovec, Oct 18 2018

Examples

			T(6,2) = 17: [6], [5,1], [4,2], [3,3], [4,1,1], [3,2,1], [2,2,1,1].
Triangle T(n,k) begins:
  0;
  0,  1;
  0,  1,  3;
  0,  3,  3,  6;
  0,  3,  8,  8, 12;
  0,  5, 11, 15, 15, 20;
  0,  8, 17, 24, 29, 29, 35;
  0, 10, 23, 36, 41, 47, 47, 54;
  0, 13, 36, 50, 65, 71, 78, 78, 86;
  ...
		

Crossrefs

Main diagonal gives A006128.
T(2n,n) gives A364245.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, [0, 0],
          add((l->[l[1], l[2]+l[1]*j])(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    T:= (n, k)-> b(n, n, k)[2]:
    seq(seq(T(n, k), k=0..n), n=0..12);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, {1, 0}, If[i < 1, {0, 0}, Sum[b[n-i*j, i-1, k] /. l_List :> {l[[1]], l[[2]] + l[[1]]*j}, {j, 0, Min[n/i, k]}]]]; T[n_, k_] := b[n, n, k][[2]]; Table[Table[T[n, k], {k, 0, n}], {n, 0, 12}] // Flatten (* Jean-François Alcover, Dec 27 2013, translated from Maple *)

Formula

T(n,k) = Sum_{i=0..k} A213177(n,i).

A320372 Number of parts in all partitions of n with largest multiplicity two.

Original entry on oeis.org

2, 0, 5, 6, 9, 13, 23, 30, 44, 58, 85, 108, 149, 191, 258, 326, 425, 532, 688, 852, 1082, 1331, 1670, 2042, 2531, 3068, 3771, 4554, 5543, 6653, 8051, 9607, 11543, 13722, 16377, 19390, 23023, 27132, 32073, 37660, 44303, 51834, 60744, 70813, 82666, 96082, 111759
Offset: 2

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=2 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l-> [0, l[1]*j]+l)(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(2):
    seq(a(n), n=2..60);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n==0, {1, 0}, If[i<1, {0, 0}, Sum[ Function[l, {0, l[[1]]*j} + l][b[n - i j, i-1, k]], {j, 0, Min[n/i, k]}]]];
    a[n_] := With[{k = 2}, (b[n, n, k] - b[n, n, k - 1])[[2]]];
    a /@ Range[2, 60] (* Jean-François Alcover, Dec 13 2020, after Alois P. Heinz *)

Formula

a(n) ~ log(3) * exp(2*Pi*sqrt(n)/3) / (2*Pi*n^(1/4)). - Vaclav Kotesovec, Oct 25 2018

A320373 Number of parts in all partitions of n with largest multiplicity three.

Original entry on oeis.org

3, 0, 4, 7, 13, 14, 27, 33, 55, 72, 107, 137, 196, 250, 344, 442, 588, 750, 982, 1234, 1591, 1992, 2523, 3135, 3944, 4857, 6035, 7408, 9121, 11109, 13599, 16465, 20004, 24122, 29112, 34927, 41952, 50078, 59836, 71169, 84625, 100219, 118716, 140061, 165225
Offset: 3

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=3 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l-> [0, l[1]*j]+l)(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(3):
    seq(a(n), n=3..60);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, {1, 0}, If[i < 1, {0, 0},        Sum[Function[l, {0, l[[1]] j} + l][b[n - i j, i - 1, k]], {j, 0, Min[n/i, k]}]]];
    a[n_] := With[{k = 3}, (b[n, n, k] - b[n, n, k - 1])[[2]]];
    a /@ Range[3, 60] (* Jean-François Alcover, Dec 13 2020, after Alois P. Heinz *)

Formula

a(n) ~ log(2) * exp(Pi*sqrt(n/2)) / (Pi * 2^(1/4) * n^(1/4)). - Vaclav Kotesovec, Oct 25 2018

A320374 Number of parts in all partitions of n with largest multiplicity four.

Original entry on oeis.org

4, 0, 5, 5, 15, 16, 30, 36, 60, 75, 116, 149, 217, 273, 386, 491, 664, 839, 1116, 1399, 1829, 2292, 2937, 3656, 4638, 5729, 7187, 8840, 10984, 13430, 16558, 20138, 24657, 29846, 36288, 43736, 52880, 63430, 76289, 91159, 109106, 129841, 154724, 183452, 217727
Offset: 4

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=4 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l->l+[0, l[1]*j])(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(4):
    seq(a(n), n=4..50);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, {1, 0}, If[i < 1, {0, 0},        Sum[Function[l, {0, l[[1]] j} + l][b[n - i j, i - 1, k]], {j, 0, Min[n/i, k]}]]];
    a[n_] := With[{k = 4}, (b[n, n, k] - b[n, n, k - 1])[[2]]];
    a /@ Range[4, 60] (* Jean-François Alcover, Dec 13 2020, after Alois P. Heinz *)

Formula

a(n) ~ 3^(1/4) * log(5) * exp(2*Pi*sqrt(2*n/15)) / (2^(5/4) * 5^(1/4) * Pi * n^(1/4)). - Vaclav Kotesovec, Oct 25 2018

A320375 Number of parts in all partitions of n with largest multiplicity five.

Original entry on oeis.org

5, 0, 6, 6, 13, 18, 34, 35, 66, 82, 120, 154, 230, 286, 408, 514, 699, 886, 1189, 1485, 1949, 2441, 3136, 3906, 4980, 6159, 7757, 9555, 11908, 14600, 18062, 22000, 27028, 32804, 39996, 48327, 58614, 70489, 85036, 101876, 122284, 145943, 174419, 207354, 246804
Offset: 5

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=5 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l->l+[0, l[1]*j])(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(5):
    seq(a(n), n=5..50);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, {1, 0}, If[i < 1, {0, 0},        Sum[Function[l, {0, l[[1]] j} + l][b[n - i j, i - 1, k]], {j, 0, Min[n/i, k]}]]];
    a[n_] := With[{k = 5}, (b[n, n, k] - b[n, n, k - 1])[[2]]];
    a /@ Range[5, 50] (* Jean-François Alcover, Dec 13 2020, after Alois P. Heinz *)

Formula

a(n) ~ log(6) * exp(Pi*sqrt(5*n)/3) / (2 * Pi * 5^(1/4) * n^(1/4)). - Vaclav Kotesovec, Oct 25 2018

A320376 Number of parts in all partitions of n with largest multiplicity six.

Original entry on oeis.org

6, 0, 7, 7, 15, 15, 38, 39, 67, 84, 131, 160, 242, 293, 421, 537, 730, 912, 1234, 1533, 2021, 2525, 3269, 4053, 5185, 6394, 8080, 9948, 12425, 15219, 18893, 23006, 28319, 34379, 42024, 50788, 61736, 74279, 89795, 107674, 129483, 154660, 185221, 220424, 262820
Offset: 6

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=6 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l->l+[0, l[1]*j])(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(6):
    seq(a(n), n=6..50);

Formula

a(n) ~ log(7) * exp(2*Pi*sqrt(n/7)) / (2 * Pi * 7^(1/4) * n^(1/4)). - Vaclav Kotesovec, Oct 25 2018

A320377 Number of parts in all partitions of n with largest multiplicity seven.

Original entry on oeis.org

7, 0, 8, 8, 17, 17, 36, 43, 74, 85, 136, 167, 254, 308, 437, 550, 754, 944, 1270, 1581, 2088, 2588, 3356, 4160, 5326, 6568, 8306, 10217, 12776, 15634, 19413, 23644, 29134, 35360, 43250, 52285, 63599, 76547, 92608, 111079, 133705, 159774, 191477, 228012, 272104
Offset: 7

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=7 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l->l+[0, l[1]*j])(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(7):
    seq(a(n), n=7..50);

Formula

a(n) ~ 3^(5/4) * log(2) * exp(Pi*sqrt(7*n/3)/2) / (2^(3/2) * 7^(1/4) * Pi * n^(1/4)). - Vaclav Kotesovec, Oct 25 2018

A320378 Number of parts in all partitions of n with largest multiplicity eight.

Original entry on oeis.org

8, 0, 9, 9, 19, 19, 40, 40, 81, 93, 140, 173, 267, 315, 461, 572, 779, 970, 1314, 1619, 2152, 2662, 3442, 4265, 5468, 6706, 8502, 10434, 13065, 15969, 19853, 24130, 29769, 36093, 44166, 53357, 64957, 78120, 94585, 113406, 136564, 163163, 195657, 232927, 278157
Offset: 8

Views

Author

Alois P. Heinz, Oct 11 2018

Keywords

Crossrefs

Column k=8 of A213177.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, [1, 0], `if`(i<1, 0,
          add((l->l+[0, l[1]*j])(b(n-i*j, i-1, k)), j=0..min(n/i, k))))
        end:
    a:= n-> (k-> (b(n$2, k)-b(n$2, k-1))[2])(8):
    seq(a(n), n=8..50);

Formula

a(n) ~ log(3) * exp(4*Pi*sqrt(n/3)/3) / (Pi * sqrt(2) * 3^(1/4) * n^(1/4)). - Vaclav Kotesovec, Oct 25 2018
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