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.

Previous Showing 21-29 of 29 results.

A002757 Number of bipartite partitions of n white objects and 8 black ones.

Original entry on oeis.org

22, 67, 181, 401, 831, 1576, 2876, 4987, 8406, 13715, 21893, 34134, 52327, 78785, 116982, 171259, 247826, 354482, 502090, 704265, 979528, 1351109, 1849932, 2514723, 3396262, 4557867, 6081466, 8068930, 10650479, 13987419, 18283999
Offset: 0

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Author

Keywords

Comments

Number of ways to factor p^n*q^8 where p and q are distinct primes.
a(n) is the number of multiset partitions of the multiset {r^n, s^8}. - Joerg Arndt, Jan 01 2024

References

  • M. S. Cheema and H. Gupta, Tables of Partitions of Gaussian Integers. National Institute of Sciences of India, Mathematical Tables, Vol. 1, New Delhi, 1956, p. 1.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column 8 of A054225.
Cf. A005380.

Programs

  • Mathematica
    p = 2; q = 3; b[n_, k_] := b[n, k] = If[n>k, 0, 1] + If[PrimeQ[n], 0, Sum[If[d>k, 0, b[n/d, d]], {d, DeleteCases[Divisors[n], 1|n]}]]; a[n_] := b[p^n*q^8, p^n*q^8]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Mar 17 2014, after Alois P. Heinz *)
    nmax = 50; CoefficientList[Series[(22 + 23*x + 25*x^2 + 16*x^3 + 4*x^4 - 14*x^5 - 34*x^6 - 50*x^7 - 65*x^8 - 52*x^9 - 32*x^10 + 5*x^11 + 27*x^12 + 57*x^13 + 67*x^14 + 65*x^15 + 42*x^16 + 15*x^17 - 14*x^18 - 34*x^19 - 40*x^20 - 46*x^21 - 26*x^22 - 8*x^23 + 8*x^24 + 11*x^25 + 18*x^26 + 14*x^27 + 9*x^28 + 3*x^29 - 7*x^30 - 7*x^31 - 6*x^32 + 3*x^33 + 3*x^34 - x^35)/((1-x) * (1-x^2) * (1-x^3) * (1-x^4) * (1-x^5) * (1-x^6) * (1-x^7) * (1-x^8)) * Product[1/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Feb 01 2016 *)

Formula

a(n) = if n <= 8 then A054225(8,n) else A054225(n,8). - Reinhard Zumkeller, Nov 30 2011
a(n) ~ 3*sqrt(3) * n^3 * exp(Pi*sqrt(2*n/3)) / (1120*Pi^8). - Vaclav Kotesovec, Feb 01 2016

Extensions

Edited by Christian G. Bower, Jan 08 2004

A002758 Number of bipartite partitions of n white objects and 9 black ones.

Original entry on oeis.org

30, 97, 267, 608, 1279, 2472, 4571, 8043, 13715, 22652, 36535, 57568, 89079, 135384, 202747, 299344, 436597, 629364, 897970, 1268634, 1776562, 2466961, 3399463, 4650218, 6318429, 8529869, 11446563, 15272827, 20269135, 26762094
Offset: 0

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Keywords

Comments

Number of ways to factor p^n*q^9 where p and q are distinct primes.
a(n) is the number of multiset partitions of the multiset {r^n, s^9}. - Joerg Arndt, Jan 01 2024

References

  • M. S. Cheema and H. Gupta, Tables of Partitions of Gaussian Integers. National Institute of Sciences of India, Mathematical Tables, Vol. 1, New Delhi, 1956, p. 2.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column 9 of A054225.
Cf. A005380.

Programs

  • Mathematica
    p = 2; q = 3; b[n_, k_] := b[n, k] = If[n>k, 0, 1] + If[PrimeQ[n], 0, Sum[If[d>k, 0, b[n/d, d]], {d, DeleteCases[Divisors[n], 1|n]}]]; a[n_] := b[p^n*q^9, p^n*q^9]; Table[a[n], {n, 0, 29}] (* Jean-François Alcover, Mar 17 2014, after Alois P. Heinz *)
    nmax = 50; CoefficientList[Series[(30 + 37*x + 43*x^2 + 37*x^3 + 20*x^4 - 3*x^5 - 35*x^6 - 65*x^7 - 97*x^8 - 119*x^9 - 109*x^10 - 69*x^11 - 26*x^12 + 37*x^13 + 89*x^14 + 131*x^15 + 142*x^16 + 141*x^17 + 97*x^18 + 44*x^19 - 18*x^20 - 72*x^21 - 100*x^22 - 108*x^23 - 96*x^24 - 69*x^25 - 25*x^26 + 12*x^27 + 42*x^28 + 52*x^29 + 54*x^30 + 35*x^31 + 14*x^32 + 2*x^33 - 4*x^34 - 20*x^35 - 19*x^36 - 14*x^37 - 8*x^38 + 7*x^39 + 8*x^40 + 8*x^41 - 2*x^42 - 4*x^43 + x^44)/((1-x) * (1-x^2) * (1-x^3) * (1-x^4) * (1-x^5) * (1-x^6) * (1-x^7) * (1-x^8) * (1-x^9)) * Product[1/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Feb 01 2016 *)

Formula

a(n) = if n <= 9 then A054225(9,n) else A054225(n,9). - Reinhard Zumkeller, Nov 30 2011
a(n) ~ n^(7/2) * exp(Pi*sqrt(2*n/3)) / (560*sqrt(2)*Pi^9). - Vaclav Kotesovec, Feb 01 2016

Extensions

Edited by Christian G. Bower, Jan 08 2004

A002759 Number of bipartite partitions of n white objects and 10 black ones.

Original entry on oeis.org

42, 139, 392, 907, 1941, 3804, 7128, 12693, 21893, 36535, 59521, 94664, 147794, 226524, 342006, 508866, 747753, 1085635, 1559725, 2218272, 3126541, 4368724, 6056705, 8333955, 11388614, 15460291, 20859497, 27979454, 37324367, 49529018
Offset: 0

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Author

Keywords

Comments

Number of ways to factor p^n*q^10 where p and q are distinct primes.
a(n) is the number of multiset partitions of the multiset {r^n, s^10}. - Joerg Arndt, Jan 01 2024

References

  • M. S. Cheema and H. Gupta, Tables of Partitions of Gaussian Integers. National Institute of Sciences of India, Mathematical Tables, Vol. 1, New Delhi, 1956, p. 2.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column 10 of A054225.
Cf. A005380.

Programs

  • Mathematica
    p = 2; q = 3; b[n_, k_] := b[n, k] = If[n>k, 0, 1] + If[PrimeQ[n], 0, Sum[If[d>k, 0, b[n/d, d]], {d, DeleteCases[Divisors[n], 1|n]}]]; a[n_] := b[p^n*q^10, p^n*q^10]; Table[a[n], {n, 0, 29}] (* Jean-François Alcover, Mar 17 2014, after Alois P. Heinz *)
    nmax = 50; CoefficientList[Series[(42 + 55*x + 72*x^2 + 68*x^3 + 55*x^4 + 22*x^5 - 21*x^6 - 72*x^7 - 126*x^8 - 178*x^9 - 222*x^10 - 203*x^11 - 169*x^12 - 81*x^13 + 15*x^14 + 125*x^15 + 209*x^16 + 286*x^17 + 303*x^18 + 299*x^19 + 219*x^20 + 107*x^21 - 4*x^22 - 117*x^23 - 208*x^24 - 263*x^25 - 257*x^26 - 232*x^27 - 151*x^28 - 69*x^29 + 29*x^30 + 92*x^31 + 130*x^32 + 145*x^33 + 143*x^34 + 97*x^35 + 48*x^36 - 2*x^37 - 39*x^38 - 48*x^39 - 58*x^40 - 41*x^41 - 31*x^42 - 19*x^43 - 4*x^44 + 19*x^45 + 21*x^46 + 20*x^47 + 13*x^48 - 4*x^49 - 9*x^50 - 10*x^51 + 2*x^52 + 4*x^53 - x^54)/((1-x) * (1-x^2) * (1-x^3) * (1-x^4) * (1-x^5) * (1-x^6) * (1-x^7) * (1-x^8) * (1-x^9) * (1-x^10)) * Product[1/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Feb 01 2016 *)

Formula

a(n) = if n <= 10 then A054225(10,n) else A054225(n,10). - Reinhard Zumkeller, Nov 30 2011
a(n) ~ sqrt(3) * n^4 * exp(Pi*sqrt(2*n/3)) / (5600*Pi^10). - Vaclav Kotesovec, Feb 01 2016

Extensions

Edited by Christian G. Bower, Jan 08 2004

A091437 Number of bipartite partitions of ceiling(n/2) white objects and floor(n/2) black ones.

Original entry on oeis.org

1, 1, 2, 4, 9, 16, 31, 57, 109, 189, 339, 589, 1043, 1752, 2998, 4987, 8406, 13715, 22652, 36535, 59521, 94664, 151958, 239241, 379693, 591271, 927622, 1431608, 2224235, 3402259, 5236586, 7947530, 12130780, 18272221, 27669593, 41393154
Offset: 0

Views

Author

Christian G. Bower, Jan 08 2004

Keywords

Crossrefs

a(n) = A054225(n, [n/2]). Cf. A002774, A005380.

Programs

  • Mathematica
    max = 35; se = Series[ Sum[ Log[1 - x^(n - k)*y^k], {n, 1, 2max}, {k, 0, n}], {x, 0, 2max}, {y, 0, 2max}]; coes = CoefficientList[ Series[ Exp[-se], {x, 0, 2max}, {y, 0, 2max}], {x, y}]; a[n_] := coes[[ Ceiling[(n+2)/2], Floor[(n+2)/2] ]]; Table[a[n], {n, 0, max} ](* Jean-François Alcover, Dec 06 2011 *)

A091438 Triangle a(n,k) of partitions of n objects of 2 colors, k of which are black and each part with at least one black object.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 3, 4, 5, 1, 3, 6, 7, 7, 1, 4, 8, 12, 12, 11, 1, 4, 10, 16, 21, 19, 15, 1, 5, 12, 23, 31, 36, 30, 22, 1, 5, 15, 28, 45, 55, 58, 45, 30, 1, 6, 17, 37, 60, 84, 94, 92, 67, 42, 1, 6, 20, 44, 80, 115, 147, 153, 140, 97, 56, 1, 7, 23, 55, 101, 161, 211, 249, 244, 211, 139, 77
Offset: 1

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Author

Keywords

Comments

Number of ways to factor p^(n-k)*q^k where p and q are distinct primes and each factor is a multiple of q.

Examples

			  1;
  1, 2;
  1, 2, 3;
  1, 3, 4, 5;
  1, 3, 6, 7, 7; ...
		

Crossrefs

Row sums: A000219.
Main diagonal: A000041.
a(2n,n) gives A108457.
Cf. A054225.

Programs

  • Maple
    b:= proc(n, i, j, k) option remember; `if`(n=0, `if`(k=0, 1, 0),
          `if`(i<1 or k<1, 0, `if`(j<1, b(n, i-1, i-1, k),
           b(n, i, j-1, k)+`if`(i>n or j>k, 0, b(n-i, i, j, k-j)))))
        end:
    a:= (n, k)->  b(n$2, k$2):
    seq(seq(a(n,k), k=1..n), n=1..15);  # Alois P. Heinz, Mar 14 2015
  • Mathematica
    b[n_, i_, j_, k_] := b[n, i, j, k] = If[n == 0, If[k == 0, 1, 0], If[i < 1 || k < 1, 0, If[j < 1, b[n, i - 1, i - 1, k], b[n, i, j - 1, k] + If[i > n || j > k, 0, b[n - i, i, j, k - j]]]]]; a[n_, k_] :=  b[n, n, k, k]; Table[a[n, k], {n, 1, 15}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jan 10 2016, after Alois P. Heinz *)

Formula

G.f.: A(x,y) = Product_{i>=1, j=1..i} (1/(1-x^i*y^j)).

A060285 Number of partitions of n objects of 2 colors with parts size >1.

Original entry on oeis.org

1, 0, 3, 4, 11, 18, 42, 70, 144, 248, 466, 802, 1442, 2444, 4247, 7116, 12030, 19878, 32938, 53670, 87429, 140680, 225815, 359100, 569157, 895224, 1402941, 2184662, 3388915, 5228458, 8035921, 12291710, 18732318, 28425342, 42981877, 64740330
Offset: 0

Views

Author

Vladeta Jovovic, Mar 23 2001

Keywords

Crossrefs

Cf. (row sums of) A060244, A054225, A005380.

Programs

  • Mathematica
    nmax=50; CoefficientList[Series[Product[1/(1-x^k)^(k+1),{k,2,nmax}],{x,0,nmax}],x] (* Vaclav Kotesovec, Mar 04 2015 *)

Formula

Euler transform of sequence [0, 3, 4, 5, 6, ...].
G.f.: Product_{k=2..infinity} 1/(1-x^k)^(k+1).
From Vaclav Kotesovec, Mar 09 2015: (Start)
For n>=2, a(n) = A005380(n-2) - 2*A005380(n-1) + A005380(n).
a(n) ~ 2^(1/36) * Zeta(3)^(37/36) * exp(1/12 - Pi^4/(432*Zeta(3)) + Pi^2 * n^(1/3) / (3*2^(4/3)*Zeta(3)^(1/3)) + 3*Zeta(3)^(1/3) * n^(2/3) / 2^(2/3)) / (A * 3^(1/2) * Pi * n^(55/36)), where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant and Zeta(3) = A002117 = 1.202056903... .
a(n) ~ (2*Zeta(3))^(2/3) * A005380(n) / n^(2/3).
(End)

Extensions

Edited by Christian G. Bower, Jan 08 2004

A054241 Number of partitions of bit-interleaved numbers; partitions of n in base sqrt(2).

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 4, 7, 2, 4, 3, 7, 9, 16, 16, 31, 5, 7, 12, 19, 11, 15, 30, 45, 29, 47, 57, 97, 77, 118, 162, 257, 5, 12, 7, 19, 29, 57, 47, 97, 11, 30, 15, 45, 77, 162, 118, 257, 109, 189, 189, 339, 323, 522, 589, 975, 323, 589, 522, 975, 1043, 1752, 1752
Offset: 0

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Author

Marc LeBrun, Feb 07 2000

Keywords

Comments

Rearrangement of A054225 via A054238. Also can be directly derived from A054240 (bit-interleaved addition table).

Examples

			a(6)=4 thus: {6, 4+2, 3+1, 2+1+1} all in base sqrt(2).
From _Sean A. Irvine_, Jan 26 2022: (Start)
a(12)=9 from {12, 9+1, 8+4, 8+1+1, 6+2, 4+2+2, 3+3, 3+2+1, 2+2+1+1}.
a(13)=16 from {13, 12+1, 9+4, 9+1+1, 8+5, 8+4+1, 8+1+1+1, 7+2, 6+3, 6+2+1, 5+2+2, 4+3+2, 4+2+2+1, 3+3+1, 3+2+1+1, 2+2+1+1+1}.
(End)
		

Crossrefs

Formula

a(n) = A054225(A054239(n)). - Sean A. Irvine, Jan 26 2022

Extensions

Data corrected by Sean A. Irvine, Jan 26 2022

A060287 Triangle formed from coefficients in expansion of Product_{i=3..infinity, j=0..i} 1/(1-x^(i-j)*y^j).

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 2, 2, 3, 4, 5, 5, 4, 3, 2, 3, 4, 6, 7, 8, 7, 6, 4, 3, 4, 6, 9, 12, 13, 13, 12, 9, 6, 4, 5, 8, 13, 17, 21, 21, 21, 17, 13, 8, 5, 6, 11, 18, 25, 31, 34, 34, 31, 25, 18, 11, 6, 9, 15, 26, 37, 48, 53, 58, 53, 48, 37, 26
Offset: 0

Views

Author

Vladeta Jovovic, Mar 23 2001

Keywords

Examples

			Series ends ... + 2*x^6 + 2*x^5*y + 3*x^4*y^2 + 3*x^3*y^3 + 3*x^2*y^4 + 2*x*y^5 + 2*y^6 + x^5 + x^4*y + x^3*y^2 + x^2*y^3 + x*y^4 + y^5 + x^4 + x^3*y + x^2*y^2 + x*y^3 + y^4 + x^3 + x^2*y + x*y^2 + y^3 + 1.
[1], [0, 0], [0, 0, 0], [1, 1, 1, 1], [1, 1, 1, 1, 1], [1, 1, 1, 1, 1, 1], [2, 2, 3, 3, 3, 2, 2], [2, 3, 4, 5, 5, 4, 3, 2], [3, 4, 6, 7, 8, 7, 6, 4, 3], ...
		

Crossrefs

A136099 Triangle read by rows: the number of ways to factor 5*2^(n-k)*3^k, columns 0<=k<=n, rows n>=0.

Original entry on oeis.org

1, 2, 2, 4, 5, 4, 7, 11, 11, 7, 12, 21, 26, 21, 12, 19, 38, 52, 52, 38, 19, 30, 64, 98, 109, 98, 64, 30, 45, 105, 171, 212, 212, 171, 105, 45, 67, 165, 289, 382, 424, 382, 289, 165, 67, 97, 254, 467, 662, 783, 783, 662, 467, 254, 97, 139, 381, 737, 1097, 1386, 1481, 1386, 1097, 737, 381, 139
Offset: 0

Views

Author

Alford Arnold, Dec 15 2007

Keywords

Comments

Second in the series of arrays beginning with A054225.

Examples

			5*A036561(2,1) = 5*6 = 30 and there are five ways to factor 30.
Triangle begins:
   1;
   2,  2;
   4,  5,  4;
   7, 11, 11,   7;
  12, 21, 26,  21, 12;
  19, 38, 52,  52, 38, 19;
  30, 64, 98, 109, 98, 64, 30;
  ...
		

Crossrefs

Formula

T(n,k) = A001055(5*A036561(n,k)).
Previous Showing 21-29 of 29 results.