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 11-18 of 18 results.

A023875 Expansion of Product_{k>=1} (1 - x^k)^(-k^6).

Original entry on oeis.org

1, 1, 65, 794, 6970, 69251, 689896, 6309849, 55654858, 483526120, 4104495070, 33968248260, 275366110929, 2192975727284, 17169583920204, 132264358228507, 1003715206329332, 7511468689508580, 55479733165442038, 404709688656248024, 2917717129031507178
Offset: 0

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Author

Keywords

Crossrefs

Column k=6 of A144048.

Programs

  • Magma
    m:=30; R:=PowerSeriesRing(Rationals(), m); Coefficients(R! ( (&*[1/(1-x^k)^k^6: k in [1..m]]) )); // G. C. Greubel, Oct 31 2018
  • Maple
    with(numtheory):
    a:= proc(n) option remember; `if`(n=0, 1,
          add(add(d*d^6, d=divisors(j)) *a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..25);  # Alois P. Heinz, Nov 02 2012
  • Mathematica
    max = 20; Series[ Product[1/(1 - x^k)^k^6, {k, 1, max}], {x, 0, max}] // CoefficientList[#, x] & (* Jean-François Alcover, Mar 05 2013 *)
  • PARI
    m=30; x='x+O('x^m); Vec(prod(k=1, m, 1/(1-x^k)^k^6)) \\ G. C. Greubel, Oct 31 2018
    

Formula

a(n) ~ exp(Pi * 2^(27/8) * n^(7/8) / (7*15^(1/8)) - 45*Zeta(7) / (8*Pi^6)) / (2^(29/16) * 15^(1/16) * n^(9/16)), where Zeta(7) = A013665 = 1.00834927738192... . - Vaclav Kotesovec, Feb 27 2015
G.f.: exp( Sum_{n>=1} sigma_7(n)*x^n/n ). - Seiichi Manyama, Mar 05 2017
a(n) = (1/n)*Sum_{k=1..n} sigma_7(k)*a(n-k). - Seiichi Manyama, Mar 05 2017

Extensions

Definition corrected by Franklin T. Adams-Watters and R. J. Mathar, Dec 04 2006

A023876 G.f.: Product_{k>=1} (1 - x^k)^(-k^7).

Original entry on oeis.org

1, 1, 129, 2316, 26956, 385017, 5512443, 70223666, 866470849, 10628564312, 126832407040, 1469751196093, 16694372607012, 186350644088784, 2042610304126944, 22007441766651756, 233482509248479425, 2441727926157182541, 25187101530316996950, 256456174925807404269
Offset: 0

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Keywords

Crossrefs

Column k=7 of A144048.

Programs

  • Magma
    m:=20; R:=PowerSeriesRing(Rationals(), m); Coefficients(R! ( (&*[1/(1-x^k)^k^7: k in [1..m]]) )); // G. C. Greubel, Oct 31 2018
  • Maple
    with(numtheory):
    a:= proc(n) option remember; `if`(n=0, 1,
          add(add(d*d^7, d=divisors(j)) *a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..20);  # Alois P. Heinz, Nov 02 2012
  • Mathematica
    max = 19; Series[ Product[1/(1 - x^k)^k^7, {k, 1, max}], {x, 0, max}] // CoefficientList[#, x] & (* Jean-François Alcover, Mar 05 2013 *)
  • PARI
    m=20; x='x+O('x^m); Vec(prod(k=1, m, 1/(1-x^k)^k^7)) \\ G. C. Greubel, Oct 31 2018
    

Formula

a(n) ~ (35*Zeta(9))^(119/2160) * exp((3/2)^(20/9) * n^(8/9) * (35*Zeta(9))^(1/9) + Zeta'(-7)) / (2^(247/2160) * 3^(961/1080) * sqrt(Pi) * n^(1199/2160)), where Zeta(9) = A013667 = 1.0020083928260822144..., Zeta'(-7) = ((gamma + log(2*Pi) - 363/140)/30 - 315*Zeta'(8)/Pi^8)/8 = -0.00072864268015924... . - Vaclav Kotesovec, Feb 27 2015

Extensions

Definition corrected by Franklin T. Adams-Watters and R. J. Mathar, Dec 04 2006

A023877 Expansion of Product_{k>=1} (1 - x^k)^(-k^8).

Original entry on oeis.org

1, 1, 257, 6818, 105250, 2175491, 44988020, 796565173, 13803604854, 240522266760, 4044067171130, 65769795259820, 1051279656603367, 16517653032316394, 254354069377336990, 3847172021760617755, 57300325471166205776, 840900188345961238222, 12164188625099191500782
Offset: 0

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Author

Keywords

Crossrefs

Column k=8 of A144048.

Programs

  • Magma
    m:=20; R:=PowerSeriesRing(Rationals(), m); Coefficients(R! ( (&*[1/(1-x^k)^k^8: k in [1..m]]) )); // G. C. Greubel, Oct 31 2018
  • Maple
    with(numtheory):
    a:= proc(n) option remember; `if`(n=0, 1,
          add(add(d*d^8, d=divisors(j)) *a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..20);  # Alois P. Heinz, Nov 02 2012
  • Mathematica
    max = 18; Series[ Product[1/(1 - x^k)^k^8, {k, 1, max}], {x, 0, max}] // CoefficientList[#, x] & (* Jean-François Alcover, Mar 05 2013 *)
  • PARI
    m=20; x='x+O('x^m); Vec(prod(k=1, m, 1/(1-x^k)^k^8)) \\ G. C. Greubel, Oct 31 2018
    

Formula

a(n) ~ exp(5 * Pi * 2^(17/10) * n^(9/10) / (3^(21/10) * 11^(1/10)) + 315*Zeta(9)/(4*Pi^8)) / (2^(13/20) * sqrt(5) * 33^(1/20) * n^(11/20)), where Zeta(9) = A013667 = 1.0020083928260822144... . - Vaclav Kotesovec, Feb 27 2015
G.f.: exp( Sum_{n>=1} sigma_9(n)*x^n/n ). - Seiichi Manyama, Mar 05 2017
a(n) = (1/n)*Sum_{k=1..n} sigma_9(k)*a(n-k). - Seiichi Manyama, Mar 05 2017

Extensions

Definition corrected by Franklin T. Adams-Watters and R. J. Mathar, Dec 04 2006

A284993 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} 1/(1+x^j)^(j^k) in powers of x.

Original entry on oeis.org

1, 1, -1, 1, -1, 0, 1, -1, -1, -1, 1, -1, -3, -2, 1, 1, -1, -7, -6, 1, -1, 1, -1, -15, -20, 0, 0, 1, 1, -1, -31, -66, -8, 11, 4, -1, 1, -1, -63, -212, -54, 99, 42, 2, 2, 1, -1, -127, -666, -284, 725, 455, 63, 8, -2, 1, -1, -255, -2060, -1350, 4935, 4580, 958, 73
Offset: 0

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Author

Seiichi Manyama, Apr 07 2017

Keywords

Examples

			Square array begins:
   1,  1,  1,   1,   1,    1, ...
  -1, -1, -1,  -1,  -1,   -1, ...
   0, -1, -3,  -7, -15,  -31, ...
  -1, -2, -6, -20, -66, -212, ...
   1,  1,  0,  -8, -54, -284, ...
		

Crossrefs

Columns k=0-5 give A081362, A255528, A284896, A284897, A284898, A284899.

Formula

G.f. of column k: Product_{j>=1} 1/(1+x^j)^(j^k).

A294296 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(Sum_{j>=1} sigma_k(j) * x^j).

Original entry on oeis.org

1, 1, 1, 1, 1, 5, 1, 1, 7, 25, 1, 1, 11, 43, 193, 1, 1, 19, 91, 409, 1481, 1, 1, 35, 223, 1105, 3841, 16021, 1, 1, 67, 595, 3505, 13841, 50431, 167665, 1, 1, 131, 1663, 12193, 60841, 230731, 648187, 2220065, 1, 1, 259, 4771, 44689, 297761, 1340851, 3955771
Offset: 0

Views

Author

Seiichi Manyama, Oct 30 2017

Keywords

Examples

			Square array A(n,k) begins:
      1,    1,     1,     1,      1, ...
      1,    1,     1,     1,      1, ...
      5,    7,    11,    19,     35, ...
     25,   43,    91,   223,    595, ...
    193,  409,  1105,  3505,  12193, ...
   1481, 3841, 13841, 60841, 297761, ...
		

Crossrefs

Columns k=0..2 give A294363, A294361, A294362.
Rows n=0-1 give A000012.
Main diagonal gives A294388.
Cf. A144048.

Formula

A(0,k) = 1 and A(n,k) = (n-1)! * Sum_{j=1..n} j*sigma_k(j)*A(n-j,k)/(n-j)! for n > 0.

A294589 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} 1/(1 - j*x^j)^(j^k).

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 1, 5, 6, 1, 1, 9, 14, 14, 1, 1, 17, 36, 42, 25, 1, 1, 33, 98, 140, 103, 56, 1, 1, 65, 276, 498, 481, 289, 97, 1, 1, 129, 794, 1844, 2419, 1774, 690, 198, 1, 1, 257, 2316, 7002, 12745, 12173, 5925, 1771, 354, 1, 1, 513, 6818, 27020, 69283, 89706, 56974, 20076, 4206, 672, 1
Offset: 0

Views

Author

Seiichi Manyama, Nov 03 2017

Keywords

Examples

			Square array begins:
    1,  1,   1,   1,    1, ...
    1,  1,   1,   1,    1, ...
    3,  5,   9,  17,   33, ...
    6, 14,  36,  98,  276, ...
   14, 42, 140, 498, 1844, ...
		

Crossrefs

Columns k=0..3 give A006906, A266941, A285241, A294590.
Rows n=0-1 give A000012.

Formula

A(0,k) = 1 and A(n,k) = (1/n) * Sum_{j=1..n} (Sum_{d|j} d^(k+1+j/d)) * A(n-j,k) for n > 0.

A319361 a(n) = [x^n] exp(Sum_{k>=1} sigma_n(k)*x^k/k).

Original entry on oeis.org

1, 1, 3, 14, 136, 2411, 88903, 6309849, 866470849, 240522266760, 132000248840652, 141226630324344532, 306101744973083495408, 1327520858367342045830198, 11328405846086223895036194126, 196814026990537767059856457640779, 6894163531963490274906095710739747873
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 17 2018

Keywords

Crossrefs

Diagonal of A144048.

Programs

  • Mathematica
    Table[SeriesCoefficient[Exp[Sum[DivisorSigma[n, k] x^k/k, {k, 1, n}]], {x, 0, n}], {n, 0, 16}]
    Table[SeriesCoefficient[Product[1/(1 - x^k)^(k^(n - 1)), {k, 1, n}], {x, 0, n}], {n, 0, 16}]

Formula

a(n) = [x^n] Product_{k>=1} 1/(1 - x^k)^(k^(n-1)).

A320251 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of 1/(1 - Sum_{j>=1} j^k*x^j).

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 3, 4, 1, 1, 5, 8, 8, 1, 1, 9, 18, 21, 16, 1, 1, 17, 44, 63, 55, 32, 1, 1, 33, 114, 207, 221, 144, 64, 1, 1, 65, 308, 723, 991, 776, 377, 128, 1, 1, 129, 858, 2631, 4805, 4752, 2725, 987, 256, 1, 1, 257, 2444, 9843, 24655, 31880, 22769, 9569, 2584, 512
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 08 2018

Keywords

Comments

A(n,k) is the invert transform of k-th powers evaluated at n.

Examples

			G.f. of column k: A_k(x) = 1 + x + (2^k + 1)*x^2 + (2^(k + 1) + 3^k + 1)*x^3 + (3*2^k + 2^(2*k + 1) + 2*3^k + 1)*x^4 + ...
Square array begins:
   1,   1,    1,    1,     1,      1,  ...
   1,   1,    1,    1,     1,      1,  ...
   2,   3,    5,    9,    17,     33,  ...
   4,   8,   18,   44,   114,    308,  ...
   8,  21,   63,  207,   723,   2631,  ...
  16,  55,  221,  991,  4805,  24655,  ...
		

Crossrefs

Columns k=0..3 give A011782, A088305, A033453, A144109.
Main diagonal gives A301655.
Cf. A144048.

Programs

  • Mathematica
    Table[Function[k, SeriesCoefficient[1/(1 - Sum[i^k x^i, {i, 1, n}]), {x, 0, n}]][j - n], {j, 0, 10}, {n, 0, j}] // Flatten
    Table[Function[k, SeriesCoefficient[1/(1 - PolyLog[-k, x]), {x, 0, n}]][j - n], {j, 0, 10}, {n, 0, j}] // Flatten

Formula

G.f. of column k: 1/(1 - PolyLog(-k,x)), where PolyLog() is the polylogarithm function.
Previous Showing 11-18 of 18 results.