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.

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A284316 Expansion of Product_{k>=0} (1 - x^(4*k+3)) in powers of x.

Original entry on oeis.org

1, 0, 0, -1, 0, 0, 0, -1, 0, 0, 1, -1, 0, 0, 1, -1, 0, 0, 2, -1, 0, -1, 2, -1, 0, -1, 3, -1, 0, -2, 3, -1, 0, -3, 4, -1, 1, -4, 4, -1, 1, -5, 5, -1, 2, -7, 5, -1, 3, -8, 6, -1, 5, -10, 6, -2, 6, -12, 7, -2, 9, -14, 7, -3, 11, -16, 8, -4, 15, -19, 8, -6, 18, -21, 9
Offset: 0

Views

Author

Seiichi Manyama, Mar 25 2017

Keywords

Crossrefs

Cf. Product_{k>=0} (1 - x^(m*k+m-1)): A081362 (m=2), A284315 (m=3), this sequence (m=4), A284317 (m=5).

Programs

  • Mathematica
    CoefficientList[Series[Product[1 - x^(4k + 3), {k, 0, 100}], {x, 0, 100}], x] (* Indranil Ghosh, Mar 25 2017 *)
  • PARI
    Vec(prod(k=0, 100, 1 - x^(4*k+3)) + O(x^101)) \\ Indranil Ghosh, Mar 25 2017

Formula

a(n) = -(1/n)*Sum_{k=1..n} A050452(k)*a(n-k), a(0) = 1.
O.g.f.: Sum_{n >= 0} (-1)^n*x^(n*(2*n+1)) / Product_{k = 1..n} ( 1 - x^(4*k) ). Cf. A284313. - Peter Bala, Nov 28 2020

A301505 Expansion of Product_{k>=1} (1 + x^(4*k))*(1 + x^(4*k-1)).

Original entry on oeis.org

1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 3, 2, 0, 2, 5, 2, 0, 4, 7, 3, 1, 7, 10, 4, 2, 11, 14, 5, 4, 17, 19, 6, 8, 25, 25, 9, 13, 36, 33, 12, 21, 50, 43, 16, 33, 69, 55, 23, 49, 93, 70, 32, 71, 124, 89, 45, 102, 163, 112, 64, 142, 212, 141, 89, 195, 273, 177, 123, 265, 349
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 22 2018

Keywords

Comments

Number of partitions of n into distinct parts congruent to 0 or 3 mod 4.

Examples

			a(11) = 3 because we have [11], [8, 3] and [7, 4].
		

Crossrefs

Programs

  • Mathematica
    nmax = 70; CoefficientList[Series[Product[(1 + x^(4 k)) (1 + x^(4 k - 1)), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 70; CoefficientList[Series[x QPochhammer[-1, x^4] QPochhammer[-x^(-1), x^4]/(2 (1 + x)), {x, 0, nmax}], x]
    nmax = 70; CoefficientList[Series[Product[(1 + Boole[MemberQ[{0, 3}, Mod[k, 4]]] x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} (1 + x^A014601(k)).
a(n) ~ exp(Pi*sqrt(n/6)) / (2^(5/2)*3^(1/4)*n^(3/4)). - Vaclav Kotesovec, Mar 23 2018

A301508 Expansion of Product_{k>=0} (1 + x^(4*k+2))*(1 + x^(4*k+3)).

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 2, 3, 4, 4, 5, 5, 6, 7, 6, 8, 9, 9, 11, 12, 13, 14, 15, 17, 19, 20, 23, 25, 27, 29, 31, 35, 37, 40, 46, 48, 52, 57, 60, 66, 71, 76, 85, 90, 97, 105, 112, 121, 129, 140, 152, 161, 174, 187, 198, 214, 228, 245, 265, 280, 302, 323, 342
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 22 2018

Keywords

Comments

Number of partitions of n into distinct parts congruent to 2 or 3 mod 4.

Examples

			a(13) = 3 because we have [11, 2], [10, 3] and [7, 6].
		

Crossrefs

Programs

  • Mathematica
    nmax = 70; CoefficientList[Series[Product[(1 + x^(4 k + 2)) (1 + x^(4 k + 3)), {k, 0, nmax}], {x, 0, nmax}], x]
    nmax = 70; CoefficientList[Series[QPochhammer[-x^2, x^4] QPochhammer[-x^3, x^4], {x, 0, nmax}], x]
    nmax = 70; CoefficientList[Series[Product[(1 + Boole[MemberQ[{2, 3}, Mod[k, 4]]] x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} (1 + x^A042964(k)).
a(n) ~ exp(Pi*sqrt(n/6)) / (4*3^(1/4)*n^(3/4)). - Vaclav Kotesovec, Mar 23 2018

A284093 Expansion of Product_{k>=1} (1 + x^(8*k-1)).

Original entry on oeis.org

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

Views

Author

Seiichi Manyama, Mar 20 2017

Keywords

Comments

Number of partitions into distinct parts 8*k-1.

Crossrefs

Cf. Product_{k>=1} (1 + x^(m*k-1)): A262928 (m=3), A147599 (m=4), A281243 (m=5), A281244 (m=6), A281245 (m=7), this sequence (m=8).

Programs

  • Mathematica
    CoefficientList[Series[Product[(1 + x^(8*k - 1)) , {k, 1, 91}], {x, 0, 91}], x] (* Indranil Ghosh, Mar 20 2017 *)
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 0; Do[If[Mod[k, 8] == 7, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly (* Vaclav Kotesovec, Mar 20 2017 *)
  • PARI
    Vec(prod(k=1, 91, (1 + x^(8*k - 1))) + O(x^92)) \\ Indranil Ghosh, Mar 20 2017

Formula

a(n) ~ exp(sqrt(n/6)*Pi/2) / (2^(21/8) * 3^(1/4) * n^(3/4)) * (1 + (11*Pi/(384*sqrt(6)) - 3*sqrt(3/2)/(2*Pi))/sqrt(n)). - Vaclav Kotesovec, Mar 20 2017
G.f.: Sum_{k>=0} x^(k*(4*k + 3)) / Product_{j=1..k} (1 - x^(8*j)). - Ilya Gutkovskiy, Nov 24 2020

A170960 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 7.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Comments

Product_{i=1..m} (1 + x^(4*i-1)) is the Poincaré polynomial for both Sp(2m) and O(2m+1).

References

  • H. Weyl, The Classical Groups, Princeton, 1946, see p. 238.

Crossrefs

Formula

a(n) = a(105-n). - Rick L. Shepherd, Mar 01 2013

A170961 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 8.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 2, 1, 0, 1, 3, 1, 0, 2, 3, 1, 0, 3, 4, 0, 1, 4, 3, 0, 1, 5, 3, 0, 2, 6, 2, 0, 3, 6, 2, 0, 5, 6, 1, 1, 5, 6, 1, 1, 7, 5, 0, 2, 7, 4, 0, 3, 8, 3, 0, 4, 7, 2, 0, 5, 7, 1, 1, 6, 5, 1, 1, 6, 5, 0, 2, 6, 3, 0, 2, 6, 2, 0, 3, 5, 1, 0, 3, 4, 1, 0, 4, 3, 0
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Comments

Product_{i=1..m} (1 + x^(4*i-1)) is the Poincaré polynomial for both Sp(2m) and O(2m+1).

References

  • H. Weyl, The Classical Groups, Princeton, 1946, see p. 238.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[Product[1+x^(4i-1),{i,8}],{x,0,110}],x] (* Harvey P. Dale, Aug 22 2012 *)

Formula

a(n) = a(136-n). - Rick L. Shepherd, Mar 01 2013

A170962 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 9.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 2, 1, 0, 1, 3, 1, 0, 2, 3, 1, 0, 3, 4, 1, 1, 4, 4, 0, 1, 5, 4, 0, 2, 7, 3, 0, 3, 7, 3, 0, 5, 8, 2, 1, 6, 8, 2, 1, 8, 8, 1, 2, 9, 7, 1, 3, 11, 7, 0, 5, 11, 5, 0, 6, 12, 4, 1, 8, 11, 3, 1, 9, 11, 2, 2, 11, 9, 1, 3, 11, 8, 1, 4, 12, 6, 0, 5, 11, 5
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Comments

Product_{i=1..m} (1 + x^(4*i-1)) is the Poincaré polynomial for both Sp(2m) and O(2m+1).

References

  • H. Weyl, The Classical Groups, Princeton, 1946, see p. 238.

Crossrefs

Formula

a(n) = a(171-n). - Rick L. Shepherd, Mar 01 2013

A170963 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 10.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 2, 1, 0, 1, 3, 1, 0, 2, 3, 1, 0, 3, 4, 1, 1, 4, 4, 1, 1, 5, 5, 0, 2, 7, 4, 0, 3, 8, 4, 0, 5, 9, 3, 1, 6, 10, 3, 1, 9, 10, 2, 2, 10, 10, 2, 3, 13, 10, 1, 5, 14, 9, 1, 7, 16, 8, 1, 9, 16, 7, 1, 11, 18, 5, 2, 14, 16, 4, 3, 16, 16, 3, 5, 18, 14
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Comments

Product_{i=1..m} (1 + x^(4*i-1)) is the Poincaré polynomial for both Sp(2m) and O(2m+1).

References

  • H. Weyl, The Classical Groups, Princeton, 1946, see p. 238.

Crossrefs

Formula

a(n) = a(210-n). - Rick L. Shepherd, Mar 01 2013

A170964 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 11.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 1, 2, 1, 0, 1, 3, 1, 0, 2, 3, 1, 0, 3, 4, 1, 1, 4, 4, 1, 1, 5, 5, 1, 2, 7, 5, 0, 3, 8, 5, 0, 5, 10, 4, 1, 6, 11, 4, 1, 9, 12, 3, 2, 11, 12, 3, 3, 14, 13, 2, 5, 16, 12, 2, 7, 19, 12, 2, 10, 20, 11, 2, 12, 23, 10, 2, 16, 23, 8, 3, 19, 24, 7, 5
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Comments

Product_{i=1..m} (1 + x^(4*i-1)) is the Poincaré polynomial for both Sp(2m) and O(2m+1).

References

  • H. Weyl, The Classical Groups, Princeton, 1946, see p. 238.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[Product[1+x^(4k-1),{k,11}],{x,0,100}],x] (* Harvey P. Dale, Sep 19 2020 *)

Formula

a(n) = a(253-n). - Rick L. Shepherd, Mar 01 2013

A309240 Expansion of 1/((1 - x)*(1 - x^2)*(1 + x^3)*(1 + x^4)*(1 - x^5)*(1 - x^6)*(1 + x^7)*(1 + x^8)*...).

Original entry on oeis.org

1, 1, 2, 1, 1, 1, 3, 3, 4, 2, 4, 4, 7, 5, 7, 6, 11, 9, 13, 10, 17, 14, 20, 15, 25, 22, 32, 24, 36, 31, 48, 38, 55, 45, 68, 55, 79, 65, 97, 79, 112, 91, 136, 113, 159, 128, 186, 156, 221, 179, 256, 213, 301, 245, 347, 290, 409, 334, 466, 388, 547, 451, 624, 517, 724, 600, 828, 687, 955, 793, 1088
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 17 2019

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 70; CoefficientList[Series[Product[1/(1 + (-1)^(k (k + 1)/2) x^k), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 70; CoefficientList[Series[Product[(1 + x^(4 k - 2))/((1 + x^(4 k - 1)) (1 - x^(4 k - 3))), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 70; CoefficientList[Series[2/(QPochhammer[-1, -x^2] QPochhammer[x, -x^2]), {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} 1/(1 + (-1)^(k*(k+1)/2) * x^k).
G.f.: Product_{k>=1} (1 + x^(4*k-2)) / ((1 + x^(4*k-1)) * (1 - x^(4*k-3))).
a(n) ~ Gamma(1/4) * exp(Pi*sqrt(n/6)) / (4 * 6^(1/8) * Pi^(3/4) * n^(5/8)). - Vaclav Kotesovec, Jul 17 2019
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