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 1-3 of 3 results.

A003956 Order of complex Clifford group of degree 2^n arising in quantum coding theory.

Original entry on oeis.org

8, 192, 92160, 743178240, 97029351014400, 203286581427673497600, 6819500449352277792129024000, 3660967964237442812098963052691456000, 31446995505814020383166371418359014222725120000
Offset: 0

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Author

Keywords

Crossrefs

Equals twice A027638.

Programs

  • GAP
    List([0..10], n-> 2^((n+1)^2 +2)*Product([1..n], j-> 4^j -1) ); # G. C. Greubel, Sep 24 2019
    
  • Magma
    [n eq 0 select 8 else 2^((n+1)^2+2)*(&*[4^j-1: j in [1..n]]): n in [0..10]]; // G. C. Greubel, Sep 24 2019
    
  • Maple
    a(n):= 2^(n^2+2*n+3)*mul(4^j-1, j=1..n); seq(a(n), n=0..10); # modified by G. C. Greubel, Sep 24 2019
  • Mathematica
    Table[2^(n^2+2n+3) Product[4^j-1,{j,n}],{n,0,10}] (* Harvey P. Dale, Nov 03 2017 *)
  • PARI
    vector(11, n, 2^(n^2 +2)*prod(j=1,n-1, 4^j-1) ) \\ G. C. Greubel, Sep 24 2019
    
  • Python
    from math import prod
    def A003956(n): return prod((1<Chai Wah Wu, Jun 20 2022
  • Sage
    [2^((n+1)^2 +2)*product(4^j -1 for j in (1..n)) for n in (0..10)] # G. C. Greubel, Sep 24 2019
    

Formula

From Amiram Eldar, Jul 06 2025: (Start)
a(n) = 2^(n^2+2*n+3) * Product_{k=1..n} (4^k-1).
a(n) ~ c * 2^(2*n^2+3*n+3), where c = A100221. (End)

A027672 Molien series for unitary 16-dimensional full Siegel modular group H_4 of order 48514675507200.

Original entry on oeis.org

1, 0, 1, 1, 2, 3, 7, 7, 19, 27, 52, 87, 172, 279, 550, 960, 1782, 3183, 5845, 10288, 18508, 32284, 56345, 96473, 164157, 274194, 454518, 741321, 1196924, 1906123, 3003750, 4673470, 7198311, 10959836, 16523847, 24654860, 36447873, 53369530, 77478005, 111498073
Offset: 0

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Keywords

Examples

			1+x^8+x^12+2*x^16+3*x^20+7*x^24+7*x^28+19*x^32+27*x^36+O(x^40).
		

Crossrefs

Programs

  • Mathematica
    (* See link for Mathematica program. *)

Formula

Oura gives an explicit formula for the Molien series.

A027633 Molien series for full 8 X 8 Siegel modular group H_3 of order 371589120.

Original entry on oeis.org

1, 0, 1, 1, 2, 2, 5, 4, 9, 10, 16, 19, 31, 34, 53, 64, 89, 109, 152, 179, 245, 296, 384, 467, 601, 716, 911, 1090, 1351, 1614, 1986, 2342, 2856, 3364, 4037, 4742, 5653, 6578, 7791, 9036, 10592, 12243, 14268, 16380, 18990, 21724, 24999
Offset: 0

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Author

Keywords

Examples

			1 + x^4 + x^6 + 2*x^8 + 2*x^10 + 5*x^12 + 4*x^14 + 9*x^16 + 10*x^18 + 16*x^20 + ...
		

Crossrefs

Cf. A027672, A027638. Bisection gives A039946.

Programs

  • Sage
    R. = PowerSeriesRing(ZZ,40);
    g = 1 + x^4 + x^10 + 3*x^16 - x^18 + 3*x^20 + 2*x^22 + 2*x^24 + 3*x^26 + 4*x^28 + 2*x^30 + 7*x^32 + 3*x^34 + 7*x^36 + 5*x^38 + 9*x^40 + 6*x^42 + 10*x^44 + 8*x^46 + 9*x^50 + 7*x^54 - x^2 + 12*x^52 + 10*x^48 + 7*x^56;
    f = g + x^112*g(1/x);
    h = f(x)*(1 + x^2)/((1 - x^4)*(1 - x^8)*(1 - x^12)^2*(1 - x^14)*(1 - x^18)*(1 - x^20)*(1 - x^30));
    [h.list()[2*i] for i in range(20)] # Andy Huchala, Mar 02 2022

Formula

Reference gives explicit formula for Molien series.
Molien series is f(x)*(1 + x^2)/((1 - x^4)*(1 - x^8)*(1 - x^12)^2*(1 - x^14)*(1 - x^18)*(1 - x^20)*(1 - x^30)),
where f(x) = g(x) + x^112*g(1/x), g(x) = 1 + x^4 + x^10 + 3*x^16 - x^18 + 3*x^20 + 2*x^22 + 2*x^24 + 3*x^26 + 4*x^28 + 2*x^30 + 7*x^32 + 3*x^34 + 7*x^36 + 5*x^38 + 9*x^40 + 6*x^42 + 10*x^44 + 8*x^46 + 9*x^50 + 7*x^54 - x^2 + 12*x^52 + 10*x^48 + 7*x^56.
Showing 1-3 of 3 results.