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 1-7 of 7 results.

A222730 Total sum T(n,k) of parts <= n of multiplicity k in all partitions of n; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

0, 0, 1, 3, 2, 1, 11, 6, 0, 1, 36, 10, 3, 0, 1, 79, 21, 3, 1, 0, 1, 186, 33, 7, 3, 1, 0, 1, 345, 59, 9, 4, 1, 1, 0, 1, 672, 89, 20, 4, 4, 1, 1, 0, 1, 1163, 145, 22, 11, 4, 2, 1, 1, 0, 1, 2026, 212, 44, 13, 6, 4, 2, 1, 1, 0, 1, 3273, 325, 56, 21, 8, 6, 2, 2, 1, 1, 0, 1
Offset: 0

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Author

Alois P. Heinz, Mar 03 2013

Keywords

Comments

For k > 0, column k is asymptotic to sqrt(3) * (2*k+1) * exp(Pi*sqrt(2*n/3)) / (2 * k^2 * (k+1)^2 * Pi^2) ~ 6 * (2*k+1) * n * p(n) / (k^2 * (k+1)^2 * Pi^2), where p(n) is the partition function A000041(n). - Vaclav Kotesovec, May 29 2018

Examples

			The partitions of n=4 are [1,1,1,1], [2,1,1], [2,2], [3,1], [4].  Parts <= 4 with multiplicity m=0 sum up to (2+3+4)+(3+4)+(1+3+4)+(2+4)+(1+2+3) = 36, for m=1 the sum is 2+(3+1)+4 = 10, for m=2 the sum is 1+2 = 3, for m=3 the sum is 0, for m=4 the sum is 1 => row 4 = [36, 10, 3, 0, 1].
Triangle T(n,k) begins:
    0;
    0,  1;
    3,  2,  1;
   11,  6,  0, 1;
   36, 10,  3, 0, 1;
   79, 21,  3, 1, 0, 1;
  186, 33,  7, 3, 1, 0, 1;
  345, 59,  9, 4, 1, 1, 0, 1;
  672, 89, 20, 4, 4, 1, 1, 0, 1;
		

Crossrefs

Programs

  • Maple
    b:= proc(n, p) option remember; `if`(n=0 and p=0, [1, 0],
          `if`(p=0, [0$(n+2)], add((l-> subsop(m+2=p*l[1]+l[m+2], l))
              ([b(n-p*m, p-1)[], 0$(p*m)]), m=0..n/p)))
        end:
    T:= n-> subsop(1=NULL, b(n, n))[]:
    seq(T(n), n=0..14);
  • Mathematica
    b[n_, p_] := b[n, p] = If[n == 0 && p == 0, {1, 0}, If[p == 0, Array[0&, n+2], Sum[Function[l, ReplacePart[l, m+2 -> p*l[[1]] + l[[m+2]]]][Join[b[n - p*m, p-1] , Array[0&, p*m]]], {m, 0, n/p}]]]; Rest /@ Table[b[n, n], {n, 0, 14}] // Flatten (* Jean-François Alcover, Dec 16 2013, translated from Maple *)

Formula

Sum_{k=0..n} k*T(n,k) = A066186(n) = n*A000041(n).
Sum_{k=1..n} T(n,k) = A014153(n-1) for n>0.
Sum_{k=0..n} T(n,k) = n*(n+1)/2*A000041(n) = A000217(n)*A000041(n).
(2 * Sum_{k=0..n} T(n,k)) / (Sum_{k=0..n} k*T(n,k)) = n+1 for n>0.
T(2*n+1,n+1) = A002865(n).

A194544 Total sum of repeated parts in all partitions of n.

Original entry on oeis.org

0, 0, 2, 3, 10, 14, 33, 46, 87, 125, 208, 291, 461, 633, 942, 1292, 1851, 2491, 3484, 4629, 6321, 8326, 11143, 14513, 19168, 24720, 32185, 41193, 53030, 67297, 85830, 108116, 136651, 171040, 214462, 266731, 332197, 410730, 508201, 625082, 768920, 940938
Offset: 0

Views

Author

Omar E. Pol, Nov 19 2011

Keywords

Examples

			For n = 6 we have:
--------------------------------------
.                          Sum of
Partitions             repeated parts
--------------------------------------
6 .......................... 0
3 + 3 ...................... 6
4 + 2 ...................... 0
2 + 2 + 2 .................. 6
5 + 1 ...................... 0
3 + 2 + 1 .................. 0
4 + 1 + 1 .................. 2
2 + 2 + 1 + 1 .............. 6
3 + 1 + 1 + 1 .............. 3
2 + 1 + 1 + 1 + 1 .......... 4
1 + 1 + 1 + 1 + 1 + 1 ...... 6
--------------------------------------
Total ..................... 33
So a(6) = 33.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; local h, j, t;
          if n<0 then [0, 0]
        elif n=0 then [1, 0]
        elif i<1 then [0, 0]
        else h:= [0, 0];
             for j from 0 to iquo(n, i) do
               t:= b(n-i*j, i-1);
               h:= [h[1]+t[1], h[2]+t[2]+`if`(j<2, 0, t[1]*i*j)]
             od; h
          fi
        end:
    a:= n-> b(n, n)[2]:
    seq(a(n), n=0..50); # Alois P. Heinz, Nov 20 2011
  • Mathematica
    b[n_, i_] := b[n, i] = Module[{h, j, t}, Which [n<0, {0, 0}, n==0, {1, 0}, i<1, {0, 0}, True, h = {0, 0}; For[j=0, j <= Quotient[n, i], j++, t = b[n - i*j, i-1]; h = {h[[1]] + t[[1]], h[[2]] + t[[2]] + If[j<2, 0, t[[1]]* i*j]}]; h]]; a[n_] := b[n, n][[2]]; Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Jan 15 2016, after Alois P. Heinz *)
    Table[Total[Flatten[Select[Flatten[Split/@IntegerPartitions[n],1], Length[ #]> 1&]]],{n,0,50}] (* Harvey P. Dale, Jan 24 2019 *)

Formula

a(n) = A066186(n) - A103628(n), n >= 1.
a(n) ~ exp(sqrt(2*n/3)*Pi) * (1/(4*sqrt(3))-3*sqrt(3)/(8*Pi^2)) * (1 - Pi*(135+2*Pi^2)/(24*(2*Pi^2-9)*sqrt(6*n))). - Vaclav Kotesovec, Nov 05 2016

Extensions

More terms from Alois P. Heinz, Nov 20 2011

A276423 Sum of the odd singletons in all partitions of n (n>=0). A singleton in a partition is a part that occurs exactly once.

Original entry on oeis.org

0, 1, 0, 4, 4, 13, 13, 33, 41, 79, 98, 171, 223, 354, 458, 692, 905, 1306, 1694, 2375, 3077, 4202, 5401, 7238, 9260, 12200, 15495, 20145, 25446, 32686, 41020, 52170, 65117, 82071, 101852, 127374, 157277, 195289, 239915, 296023, 362000, 444063, 540595, 659662
Offset: 0

Views

Author

Emeric Deutsch, Sep 14 2016

Keywords

Examples

			a(4) = 4 because in the partitions [1,1,1,1], [1,1,2], [2,2], [1,3], [4] the sums of the odd singletons are 0,0,0,4,0, respectively; their sum is 4.
a(5) = 13 because in the partitions [1,1,1,1,1], [1,1,1,2], [1,2,2], [1,1,3], [2,3], [1,4], [5] the sums of the odd singletons are 0,0,1,3,3,1,5, respectively; their sum is 13.
		

Crossrefs

Programs

  • Maple
    g := x*(1-x+3*x^2+3*x^4-x^5+x^6)/((1-x^4)^2*(product(1-x^i, i = 1..120))): gser := series(g, x = 0, 60); 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::odd and j=1,
          [0, i*p[1]], 0))(b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..50); # Alois P. Heinz, Sep 14 2016
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, {1, 0}, If[i < 1, 0, Sum[Function[p, p + If[OddQ[i] && j == 1, {0, If[p === 0, 0, i*p[[1]]]}, 0]][b[n-i*j, i-1]], {j, 0, n/i}]]]; a[n_] := b[n, n][[2]]; Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Dec 04 2016 after Alois P. Heinz *)
    Table[Total[Select[Flatten[Tally/@IntegerPartitions[n],1],#[[2]]==1 && OddQ[ #[[1]]]&][[All,1]]],{n,0,50}] (* Harvey P. Dale, May 25 2018 *)

Formula

G.f.: g(x) = x*(1-x+3*x^2+3*x^4-x^5+x^6)/((1-x^4)^2*Product_{j>=1} 1-x^j).
a(n) = Sum_{k>=0} k*A276422(n,k).
a(n) ~ 3^(3/2) * exp(Pi*sqrt(2*n/3)) / (16*Pi^2). - Vaclav Kotesovec, Jun 12 2025

A276425 Sum of the even singletons in all partitions of n (n>=0). A singleton in a partition is a part that occurs exactly once.

Original entry on oeis.org

0, 0, 2, 2, 6, 8, 20, 26, 48, 66, 114, 154, 240, 326, 490, 656, 940, 1252, 1752, 2306, 3142, 4104, 5500, 7114, 9372, 12030, 15656, 19932, 25628, 32402, 41270, 51816, 65400, 81608, 102226, 126800, 157698, 194550, 240454, 295110, 362600, 442902, 541342, 658230
Offset: 0

Views

Author

Emeric Deutsch, Sep 14 2016

Keywords

Examples

			a(4) = 6 because in the partitions [1,1,1,1], [1,1,2], [2,2], [1,3], [4] the sums of the even singletons are 0, 2, 0, 0, 4, respectively; their sum is 6.
a(5) = 8 because in the partitions [1,1,1,1,1], [1,1,1,2], [1,2,2], [1,1,3], [2,3], [1,4], [5] the sums of the even singletons are 0, 2, 0, 0, 2, 4, 0 respectively; their sum is 8.
		

Crossrefs

Programs

  • Maple
    g := 2*x^2*(1+x^2+x^4)/((1-x^4)^2*(product(1-x^i, i = 1 .. 120))): gser := series(g, x = 0, 60): 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::even and j=1,
          [0, i*p[1]], 0))(b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=0..50);  # Alois P. Heinz, Sep 14 2016
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, {1, 0}, If[i<1, 0, Sum[Function[p, p + If[EvenQ[i] && j == 1, {0, i*p[[1]]}, 0]][b[n-i*j, i-1]], {j, 0, n/i}]]]; a[n_] := b[n, n][[2]]; Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Oct 24 2016, after Alois P. Heinz *)

Formula

G.f.: g(x) = 2x^2*(1+x^2+x^4)/((1-x^4)^2 product(1-x^j, j>=1)).
a(n) = Sum(k*A276424(n,k), k>=0).
a(n) ~ 3^(3/2) * exp(Pi*sqrt(2*n/3)) / (16*Pi^2). - Vaclav Kotesovec, Jun 12 2025

A117525 Total sum of parts of multiplicity 2 in all partitions of n.

Original entry on oeis.org

0, 0, 1, 0, 3, 3, 7, 9, 20, 22, 44, 56, 90, 119, 186, 236, 355, 461, 651, 848, 1177, 1506, 2050, 2626, 3482, 4443, 5823, 7353, 9524, 11983, 15307, 19163, 24277, 30174, 37920, 46925, 58463, 72006, 89155, 109209, 134418, 163973, 200605, 243700, 296696, 358862
Offset: 0

Views

Author

Vladeta Jovovic, Apr 26 2006

Keywords

Comments

For m > 0, column m of A222730 is asymptotic to sqrt(3) * (2*m+1) * exp(Pi*sqrt(2*n/3)) / (2 * m^2 * (m+1)^2 * Pi^2) ~ 6 * (2*m+1) * n * p(n) / (m^2 * (m+1)^2 * Pi^2), where p(n) is the partition function A000041(n). - Vaclav Kotesovec, May 29 2018

Examples

			a(5) = 3 because the partitions of 5 that have parts with multiplicity 2 are [3,1,1] and [2,2,1] and the sum of those parts is 1+2 = 3.
		

Crossrefs

Cf. A103628.
Column k=2 of A222730. - Alois P. Heinz, Mar 03 2013

Programs

  • Maple
    g:=(x^2/(1-x^2)^2-x^3/(1-x^3)^2)/Product(1-x^i,i=1..60): gser:=series(g,x=0,55): seq(coeff(gser,x,n),n=0..50); # Emeric Deutsch, May 13 2006
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<1, [0, 0],
          add((l->`if`(j=2, [l[1], l[2]+l[1]*i], l))(b(n-i*j, i-1)), j=0..n/i)))
        end:
    a:= n-> b(n, n)[2]:
    seq(a(n), n=0..50);  # Alois P. Heinz, Feb 03 2013
  • Mathematica
    b[n_, p_] := b[n, p] = If[n == 0 && p == 0, {1, 0}, If[p == 0, Array[0&, n+2], Sum[Function[l, ReplacePart[l, m+2 -> p*l[[1]] + l[[m+2]]]][Join[b[n-p*m, p-1], Array[0&, p*m]]], {m, 0, n/p}]]]; a[n_] := b[n, n][[4]]; a[0] = a[1] = 0; Table[a[n], {n, 0, 50}]   (* Jean-François Alcover, Jan 24 2014, after Alois P. Heinz *)

Formula

G.f. for total sum of parts of multiplicity m in all partitions of n is (x^m/(1-x^m)^2-x^(m+1)/(1-x^(m+1))^2)/Product(1-x^i,i=1..infinity).
a(n) ~ 5 * sqrt(3) * exp(Pi*sqrt(2*n/3)) / (72 * Pi^2). - Vaclav Kotesovec, May 29 2018

Extensions

More terms from Emeric Deutsch, May 13 2006

A213180 Sum over all partitions lambda of n of Sum_{p:lambda} p^m(p,lambda), where m(p,lambda) is the multiplicity of part p in lambda.

Original entry on oeis.org

0, 1, 3, 7, 16, 28, 59, 91, 170, 269, 450, 655, 1162, 1602, 2527, 3793, 5805, 8034, 12660, 17131, 26484, 37384, 53738, 73504, 114683, 153613, 221225, 313339, 453769, 609179, 927968, 1223909, 1804710, 2522264, 3539835, 4855420, 7439870, 9765555, 14009545
Offset: 0

Views

Author

Alois P. Heinz, Feb 27 2013

Keywords

Examples

			a(6) = 59: (1^6) + (2+1^4) + (2^2+1^2) + (2^3) + (3+1^3) + (3+2+1) + (3^2) + (4+1^2) + (4+2) + (5+1) + (6) = 1+3+5+8+4+6+9+5+6+6+6 = 59.
		

Crossrefs

Cf. A000070 (Sum 1), A006128 (Sum m), A014153 (Sum p), A024786 (Sum floor(1/m)), A066183 (Sum p^2*m), A066186 (Sum p*m), A073336 (Sum floor(m/p)), A116646 (Sum delta(m,2)), A117524 (Sum delta(m,3)), A103628 (Sum delta(m,1)*p), A117525 (Sum delta(m,2)*p), A197126, A213191.

Programs

  • Maple
    b:= proc(n, p) option remember; `if`(n=0, [1, 0], `if`(p<1, [0, 0],
          add((l->`if`(m=0, l, l+[0, l[1]*p^m]))(b(n-p*m, p-1)), m=0..n/p)))
        end:
    a:= n-> b(n, n)[2]:
    seq(a(n), n=0..40);
  • Mathematica
    b[n_, p_] := b[n, p] = If[n==0, {1, 0}, If[p<1, {0, 0}, Sum[Function[l, If[m==0, l, l+{0, l[[1]]*p^m}]][b[n-p*m, p-1]], {m, 0, n/p}]]]; a[n_] := b[n, n][[2]]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Feb 15 2017, translated from Maple *)

Formula

From Vaclav Kotesovec, May 24 2018: (Start)
a(n) ~ c * 3^(n/3), where
c = 5.0144820680945600131204662934686439430547... if mod(n,3)=0
c = 4.6144523178014379613985400559486878971522... if mod(n,3)=1
c = 4.5237761454818383598444208605033385016299... if mod(n,3)=2
(End)

A264403 Triangle read by rows: T(n,k) is the number of partitions of n in which the sum of the parts of multiplicity 1 is equal to k (0<=k<=n).

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 1, 0, 0, 2, 2, 0, 1, 0, 2, 1, 1, 1, 1, 0, 3, 4, 0, 1, 1, 1, 0, 4, 2, 2, 1, 2, 1, 2, 0, 5, 6, 0, 2, 1, 3, 2, 2, 0, 6, 5, 2, 1, 4, 1, 4, 2, 3, 0, 8, 9, 1, 3, 2, 5, 2, 4, 3, 3, 0, 10, 7, 3, 3, 6, 2, 7, 2, 6, 3, 5, 0, 12, 16, 0, 4, 4, 7, 3, 8, 3, 7, 5, 5, 0, 15, 11, 6, 4, 8, 5, 9, 3, 12, 3, 10, 5, 7, 0, 18
Offset: 0

Views

Author

Emeric Deutsch, Nov 27 2015

Keywords

Comments

Row n contains n+1 entries (n>=0).
Row sums yield the partition numbers (A000041).
T(n,0) = A007690(n).
T(n,n) = A000009(n).
Sum_{k>=0} k*T(n,k) = A103628(n).

Examples

			T(7,5) = 2 because we have [3,2,1,1] and [5,1,1].
Triangle starts:
1;
0,1;
1,0,1;
1,0,0,2;
2,0,1,0,2;
		

Crossrefs

Programs

  • Maple
    g := product(1+t^j*x^j+x^(2*j)/(1-x^j), j = 1 .. 100): gser := simplify(series(g, x = 0, 25)): for n from 0 to 20 do P[n] := sort(coeff(gser, x, n)) end do: for n from 0 to 20 do seq(coeff(P[n], t, k), k = 0 .. n) end do; # yields sequence in triangular form
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, 1,
          `if`(i<1, 0, add(expand(b(n-i*j, i-1)*
          `if`(j=1, x^i, 1)), j=0..n/i)))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n$2)):
    seq(T(n), n=0..15);  # Alois P. Heinz, Nov 27 2015
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0, 1, If[i<1, 0, Sum[Expand[b[n-i*j, i-1]*If[j == 1, x^i, 1]], {j, 0, n/i}]]]; T[n_] := Function[p,Table[Coefficient[p, x, i], {i, 0, n}]][b[n, n]]; Table[T[n], {n, 0, 15}] // Flatten (* Jean-François Alcover, Jan 29 2016, after Alois P. Heinz *)

Formula

G.f.: G(t,x) = Product_{j>=1} (1+t^j*x^j + x^{2*j}/(1 - x^j)).
Showing 1-7 of 7 results.