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 35 results. Next

A261612 Expansion of Product_{k>=0} (1 + x^(3*k+1)).

Original entry on oeis.org

1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 2, 1, 1, 2, 1, 1, 3, 2, 1, 3, 3, 2, 4, 4, 2, 4, 5, 3, 5, 7, 4, 5, 8, 6, 7, 10, 7, 7, 12, 10, 9, 14, 12, 10, 16, 16, 13, 19, 19, 15, 22, 24, 19, 25, 28, 22, 29, 35, 28, 33, 40, 33, 38, 48, 41, 44, 55, 48, 51, 66, 59, 58, 74, 69
Offset: 0

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Author

Vaclav Kotesovec, Aug 26 2015

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 + x^(3*k+1)), {k, 0, nmax}], {x, 0, nmax}], x]
    nmax = 100; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 1; Do[If[Mod[k, 3] == 1, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}];], {k, 2, nmax}]; poly (* Vaclav Kotesovec, Jan 13 2017 *)

Formula

a(n) ~ exp(Pi*sqrt(n)/3) / (2^(4/3) * sqrt(3) * n^(3/4)) * (1 - (Pi/144 + 9/(8*Pi)) / sqrt(n)). - Vaclav Kotesovec, Aug 26 2015, extended Jan 16 2017
G.f.: Sum_{k>=0} x^(k*(3*k - 1)/2) / Product_{j=1..k} (1 - x^(3*j)). - Ilya Gutkovskiy, Nov 24 2020

A147599 Expansion of Product_{i>=1} (1+x^(4*i-1)).

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, 8, 23, 24, 10, 11, 27, 27, 11, 14, 34, 30, 12, 19, 39, 33, 14, 24, 47
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Comments

Number of partitions into distinct parts 4*k+3.
Convolution of A147599 and A169975 is A000700. - Vaclav Kotesovec, Jan 18 2017

Crossrefs

Programs

  • Mathematica
    nmax = 200; CoefficientList[Series[Product[(1 + x^(4*k - 1)), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jan 18 2017 *)
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 0; Do[If[Mod[k, 4] == 3, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly (* Vaclav Kotesovec, Jan 18 2017 *)

Formula

G.f. sum(n>=0, x^(2*n^2+n) / prod(k=1,n, 1-x^(4*k))) - Joerg Arndt, Mar 10 2011.
a(n) ~ exp(sqrt(n/3)*Pi/2) / (4*6^(1/4)*n^(3/4)) * (1 - (3*sqrt(3)/(4*Pi) + Pi/(192*sqrt(3))) / sqrt(n)). - Vaclav Kotesovec, Jan 18 2017

A281243 Expansion of Product_{k>=1} (1 + x^(5*k-1)).

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 2, 1, 0, 0, 1, 2, 1, 0, 0, 1, 3, 1, 0, 0, 2, 3, 1, 0, 0, 3, 4, 1, 0, 1, 4, 4, 1, 0, 1, 5, 5, 1, 0, 2, 7, 5, 1, 0, 3, 8, 6, 1, 0, 5, 10, 6, 1, 1, 6, 12, 7, 1, 1, 9, 14, 7, 1, 2, 11, 16, 8, 1
Offset: 0

Views

Author

Vaclav Kotesovec, Jan 18 2017

Keywords

Comments

Convolution of this sequence and A280454 is A203776.

Crossrefs

Programs

  • Mathematica
    nmax = 200; CoefficientList[Series[Product[(1 + x^(5*k - 1)), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 0; Do[If[Mod[k, 5] == 4, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly

Formula

a(n) ~ exp(sqrt(n/15)*Pi) / (2^(9/5)*15^(1/4)*n^(3/4)) * (1 + (Pi/(240*sqrt(15)) - 3*sqrt(15)/(8*Pi)) / sqrt(n)). - Vaclav Kotesovec, Jan 18 2017, extended Jan 24 2017
G.f.: Sum_{k>=0} x^(k*(5*k + 3)/2) / Product_{j=1..k} (1 - x^(5*j)). - Ilya Gutkovskiy, Nov 24 2020

A280454 Expansion of Product_{k>=0} (1 + x^(5*k+1)).

Original entry on oeis.org

1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 2, 1, 0, 0, 1, 2, 1, 0, 0, 1, 3, 2, 0, 0, 1, 3, 3, 1, 0, 1, 4, 4, 1, 0, 1, 4, 5, 2, 0, 1, 5, 7, 3, 0, 1, 5, 8, 5, 1, 1, 6, 10, 6, 1, 1, 6, 12, 9, 2, 1, 7, 14, 11, 3, 1, 7, 16, 15, 5, 1, 8, 19, 18, 7, 2, 8, 21, 23, 10, 2, 9, 24, 27, 13, 3, 9, 27, 34, 18, 4, 10, 30, 39, 23, 6, 10
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 03 2017

Keywords

Comments

Number of partitions of n into distinct parts congruent to 1 mod 5.
Convolution of A281243 and A280454 is A203776. - Vaclav Kotesovec, Jan 18 2017

Examples

			a(27) = 3 because we have [26, 1], [21, 6] and [11, 16].
		

Crossrefs

Programs

  • Mathematica
    nmax = 102; CoefficientList[Series[Product[(1 + x^(5 k + 1)), {k, 0, nmax}], {x, 0, nmax}], x]
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 1; Do[If[Mod[k, 5] == 1, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly (* Vaclav Kotesovec, Jan 18 2017 *)

Formula

G.f.: Product_{k>=0} (1 + x^(5*k+1)).
a(n) ~ exp(Pi*sqrt(n)/sqrt(15))/(2*2^(1/5)*15^(1/4)*n^(3/4)) * (1 + (Pi/(240*sqrt(15)) - 3*sqrt(15)/(8*Pi)) / sqrt(n)). - Ilya Gutkovskiy, Jan 03 2017, extended by Vaclav Kotesovec, Jan 24 2017

A281245 Expansion of Product_{k>=1} (1 + x^(7*k-1)).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Jan 18 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 200; CoefficientList[Series[Product[(1 + x^(7*k - 1)), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 0; Do[If[Mod[k, 7] == 6, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly

Formula

a(n) ~ exp(sqrt(n/21)*Pi) / (2^(13/7)*21^(1/4)*n^(3/4)) * (1 + (13*Pi/(336*sqrt(21)) - 3*sqrt(21)/(8*Pi)) / sqrt(n)). - Vaclav Kotesovec, Jan 18 2017, extended Jan 24 2017
G.f.: Sum_{k>=0} x^(k*(7*k + 5)/2) / Product_{j=1..k} (1 - x^(7*j)). - Ilya Gutkovskiy, Nov 24 2020

A280457 Expansion of Product_{k>=0} (1 + x^(7*k+1)).

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Jan 03 2017

Keywords

Comments

Number of partitions of n into distinct parts congruent to 1 mod 7.

Examples

			a(37) = 3 because we have [36, 1], [29, 8] and [22, 15].
		

Crossrefs

Programs

  • Mathematica
    nmax = 105; CoefficientList[Series[Product[(1 + x^(7 k + 1)), {k, 0, nmax}], {x, 0, nmax}], x]
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 1; Do[If[Mod[k, 7] == 1, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly (* Vaclav Kotesovec, Jan 18 2017 *)

Formula

G.f.: Product_{k>=0} (1 + x^(7*k+1)).
a(n) ~ exp(Pi*sqrt(n)/sqrt(21))/(2*2^(1/7)*21^(1/4)*n^(3/4)) * (1 + (13*Pi/(336*sqrt(21)) - 3*sqrt(21)/(8*Pi)) / sqrt(n)). - Ilya Gutkovskiy, Jan 03 2017, extended by Vaclav Kotesovec, Jan 24 2017

A170956 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 3.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1
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

A170965 Expansion of Product_{i=1..m} (1 + x^(4*i-1)) for m = 12.

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, 0, 5, 10, 5, 1, 6, 12, 5, 1, 9, 13, 4, 2, 11, 14, 4, 3, 15, 15, 3, 5, 17, 15, 3, 7, 21, 15, 3, 10, 23, 15, 3, 13, 27, 14, 3, 17, 28, 13, 4, 21, 31, 12
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,12}],{x,0,100}],x] (* Harvey P. Dale, Dec 24 2012 *)

A281244 Expansion of Product_{k>=1} (1 + x^(6*k-1)).

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 2, 1, 0, 0, 0, 1, 2, 1, 0, 0, 0, 1, 3, 1, 0, 0, 0, 2, 3, 1, 0, 0, 0, 3, 4, 1, 0, 0, 1, 4, 4, 1, 0, 0, 1, 5, 5, 1, 0, 0, 2, 7, 5, 1, 0, 0, 3, 8, 6, 1, 0, 0, 5, 10, 6, 1, 0, 1
Offset: 0

Views

Author

Vaclav Kotesovec, Jan 18 2017

Keywords

Comments

Convolution of this sequence and A280456 is A098884.

Crossrefs

Programs

  • Maple
    a:= proc(n) option remember; `if`(n=0, 1, add(add(
          [0$5, 1, 0$4, -1, 1][1+irem(d, 12)]*d, d=
           numtheory[divisors](j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..100);  # Alois P. Heinz, Jan 18 2017
  • Mathematica
    nmax = 200; CoefficientList[Series[Product[(1 + x^(6*k - 1)), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 200; poly = ConstantArray[0, nmax + 1]; poly[[1]] = 1; poly[[2]] = 0; Do[If[Mod[k, 6] == 5, Do[poly[[j + 1]] += poly[[j - k + 1]], {j, nmax, k, -1}]; ], {k, 2, nmax}]; poly

Formula

a(n) ~ exp(sqrt(n/2)*Pi/3) / (2^(25/12)*sqrt(3)*n^(3/4)) * (1 + (Pi/144 - 9/(4*Pi)) / sqrt(2*n)).
G.f.: Sum_{k>=0} x^(k*(3*k + 2)) / Product_{j=1..k} (1 - x^(6*j)). - Ilya Gutkovskiy, Nov 24 2020

A170966 Expansion of Product_{i=0..m-1} (1 + x^(4*i+1)) for m = 3.

Original entry on oeis.org

1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1
Offset: 0

Views

Author

N. J. A. Sloane, Aug 29 2010

Keywords

Crossrefs

Showing 1-10 of 35 results. Next