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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A006101 Gaussian binomial coefficient [ n,3 ] for q=3.

Original entry on oeis.org

1, 40, 1210, 33880, 925771, 25095280, 678468820, 18326727760, 494894285941, 13362799477720, 360801469802830, 9741692640081640, 263026177881648511, 7101711092201899360, 191746238094034963240, 5177148775980218655520, 139783020078437440101481
Offset: 3

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Author

Keywords

References

  • J. Goldman and G.-C. Rota, The number of subspaces of a vector space, pp. 75-83 of W. T. Tutte, editor, Recent Progress in Combinatorics. Academic Press, NY, 1969.
  • I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p. 99.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Programs

  • Magma
    r:=3; q:=3; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Nov 06 2016
  • Mathematica
    Table[QBinomial[n, 3, 3], {n, 3, 20}] (* Vincenzo Librandi, Nov 06 2016 *)
  • Sage
    [gaussian_binomial(n,3,3) for n in range(3,17)] # Zerinvary Lajos, May 25 2009
    

Formula

G.f.: z^3/((1-z)(1-3z)(1-9z)(1-27z)). Simon Plouffe in his 1992 dissertation
a(n) = (27^n - 13*9^n + 39*3^n - 27)/11232. - Mitch Harris, Mar 23 2008

A203241 Second elementary symmetric function of the first n terms of (1,2,4,8,...).

Original entry on oeis.org

2, 14, 70, 310, 1302, 5334, 21590, 86870, 348502, 1396054, 5588310, 22361430, 89462102, 357881174, 1431590230, 5726491990, 22906230102, 91625444694, 366502827350, 1466013406550, 5864057820502, 23456239670614, 93824975459670
Offset: 2

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Author

Clark Kimberling, Dec 31 2011

Keywords

Crossrefs

Cf. A006095.

Programs

  • Mathematica
    f[k_] := 2^(k - 1); t[n_] := Table[f[k], {k, 1, n}]
    a[n_] := SymmetricPolynomial[2, t[n]]
    Table[a[n], {n, 2, 32}]    (* A203241 *)
    Table[a[n]/2, {n, 2, 32}]  (* A006095 *)
  • PARI
    Vec(-2*x^2 / ((x-1)*(2*x-1)*(4*x-1)) + O(x^100)) \\ Colin Barker, Aug 15 2014

Formula

a(n) = 2*A006095(n).
From Colin Barker, Aug 15 2014: (Start)
a(n) = (2 - 3*2^n + 4^n)/3.
a(n) = 7*a(n-1) - 14*a(n-2) + 8*a(n-3).
G.f.: -2*x^2 / ((x-1)*(2*x-1)*(4*x-1)). (End)
a(n) = Sum_{k=0...n-2} 2^k*(2^(n-1)-1+2^k). - J. M. Bergot, Mar 21 2018

A022191 Gaussian binomial coefficients [n, 8] for q = 2.

Original entry on oeis.org

1, 511, 174251, 50955971, 13910980083, 3675639930963, 955841412523283, 246614610741341843, 63379954960524853651, 16256896431763117598611, 4165817792093527797314451, 1066968301301093995246996371, 273210326382611632738979052435
Offset: 8

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Author

Keywords

Crossrefs

Gaussian binomial coefficient [n, k] for q = 2: A000225 (k = 1), A006095 (k = 2), A006096 (k = 3), A006097 (k = 4), A006110 (k = 5), A022189 - A022195 (k = 6 thru 12).

Programs

  • Magma
    r:=8; q:=2; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 03 2016
    
  • Mathematica
    Table[QBinomial[n, 8, 2], {n, 8, 40}] (* Vincenzo Librandi, Aug 03 2016 *)
  • PARI
    r=8; q=2; for(n=r,30, print1(prod(j=1,r,(1-q^(n-j+1))/(1-q^j)), ", ")) \\ G. C. Greubel, May 30 2018
  • Sage
    [gaussian_binomial(n,8,2) for n in range(8,20)] # Zerinvary Lajos, May 25 2009
    

Formula

a(n) = Product_{i=1..8} (2^(n-i+1)-1)/(2^i-1), by definition. - Vincenzo Librandi, Aug 03 2016
G.f. with an offset of 0: exp( Sum_{n >= 1} b(9*n)/b(n)*x^n/n ) = 1 + 511*x +174251*x^2 + ..., where b(n) = A000225(n) = 2^n - 1. - Peter Bala, Jul 01 2025

Extensions

Offset changed by Vincenzo Librandi, Aug 03 2016

A022192 Gaussian binomial coefficients [n, 9] for q = 2.

Original entry on oeis.org

1, 1023, 698027, 408345795, 222984027123, 117843461817939, 61291693863308051, 31627961868755063955, 16256896431763117598611, 8339787869494479328087443, 4274137206973266943778085267, 2189425218271613769209626653075
Offset: 9

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Author

Keywords

Crossrefs

Gaussian binomial coefficient [n, k] for q = 2: A000225 (k = 1), A006095 (k = 2), A006096 (k = 3), A006097 (k = 4), A006110 (k = 5), A022189 - A022195 (k = 6 thru 12).

Programs

  • Magma
    r:=9; q:=2; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 03 2016
    
  • Maple
    seq(eval(expand(QDifferenceEquations:-QBinomial(n,9,q)),q=2),n=9..50);
  • Mathematica
    QBinomial[Range[9,20],9,2] (* Harvey P. Dale, Jul 24 2016 *)
  • PARI
    r=9; q=2; for(n=r,30, print1(prod(j=1,r,(1-q^(n-j+1))/(1-q^j)), ", ")) \\ G. C. Greubel, May 30 2018
  • Sage
    [gaussian_binomial(n,9,2) for n in range(9,21)] # Zerinvary Lajos, May 25 2009
    

Formula

a(n) = Product_{i=1..9} (2^(n-i+1)-1)/(2^i-1), by definition. - Vincenzo Librandi, Aug 02 2016
G.f.: x^9/Product_{0<=i<=9} (1-2^i*x). - Robert Israel, Apr 23 2017
G.f. with an offset of 0: exp( Sum_{n >= 1} b(10*n)/b(n)*x^n/n ) = 1 + 1023*x + 698027*x^2 + ..., where b(n) = A000225(n) = 2^n - 1. - Peter Bala, Jul 01 2025

Extensions

Offset changed by Vincenzo Librandi, Aug 03 2016

A097038 A Jacobsthal variant.

Original entry on oeis.org

0, 1, 1, 5, 7, 21, 35, 85, 155, 341, 651, 1365, 2667, 5461, 10795, 21845, 43435, 87381, 174251, 349525, 698027, 1398101, 2794155, 5592405, 11180715, 22369621, 44731051, 89478485, 178940587, 357913941, 715795115, 1431655765, 2863245995
Offset: 0

Views

Author

Paul Barry, Jul 19 2004

Keywords

Comments

Convolution of A001045 and A077957.
Also interleaving of A002450(n+1) and A006095(n+1).

Crossrefs

Programs

  • PARI
    concat(0, Vec(x/((1-2*x^2)*(1-x-2*x^2)) + O(x^50))) \\ Michel Marcus, Nov 13 2015
    
  • PARI
    vector(50, n, n--; 2*2^n/3+(-1)^n/3-2^(n/2)*(1+(-1)^n)/2) \\ Altug Alkan, Nov 13 2015

Formula

G.f.: 1/(1-x-2*x^2) - 1/(1-2*x^2) = x/((1-2*x^2)*(1-x-2*x^2));
a(n) = 2*2^n/3+(-1)^n/3-2^(n/2)*(1+(-1)^n)/2;
a(n) = sum{k=0..floor((n+1)/2), binomial(n-k+1, k-1)2^k };
a(n) = sum{k=0..n, 2^(k/2)(1+(-1)^k)A001045(n-k)/2 };
a(n) = A001045(n+1)-A077957(n).

A128119 Square array T(n,m) read by antidiagonals: number of sublattices of index m in generic n-dimensional lattice.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 7, 4, 1, 1, 15, 13, 7, 1, 1, 31, 40, 35, 6, 1, 1, 63, 121, 155, 31, 12, 1, 1, 127, 364, 651, 156, 91, 8, 1, 1, 255, 1093, 2667, 781, 600, 57, 15, 1, 1, 511, 3280, 10795, 3906, 3751, 400, 155, 13, 1, 1, 1023, 9841, 43435, 19531, 22932, 2801, 1395, 130, 18, 1
Offset: 1

Views

Author

Ralf Stephan, May 09 2007

Keywords

Comments

Differs from sum of divisors of m^(n-1) in 4th column!

Examples

			Array starts:
1,1,1,1,1,1,1,1,1,
1,3,4,7,6,12,8,15,13,
1,7,13,35,31,91,57,155,130,
1,15,40,155,156,600,400,1395,1210,
1,31,121,651,781,3751,2801,11811,11011,
1,63,364,2667,3906,22932,19608,97155,99463,
1,127,1093,10795,19531,138811,137257,788035,896260,
1,255,3280,43435,97656,836400,960800,6347715,8069620,
		

References

  • Günter Scheja, Uwe Storch, Lehrbuch der Algebra, Teil 2. BG Teubner, Stuttgart, 1988. [§63, Aufg. 13]

Crossrefs

Programs

  • Mathematica
    T[n_, m_] := If[m == 1, 1, Product[{p, e} = pe; (p^(e+j)-1)/(p^j-1), {pe, FactorInteger[m]}, {j, 1, n-1}]];
    Table[T[n-m+1, m], {n, 1, 11}, {m, 1, n}] // Flatten (* Jean-François Alcover, Dec 10 2018 *)
  • PARI
    T(n,m)=local(k,v);v=factor(m);k=matsize(v)[1];prod(i=1,k,prod(j=1,n-1,(v[i,1]^(v[i,2]+j)-1)/(v[i,1]^j-1)))

Formula

Dirichlet g.f. of n-th row: Product_{i=0..n-1} zeta(s-i).
If m is squarefree, T(n,m) = A000203(m^(n-1)). - Álvar Ibeas, Jan 17 2015
T(n, Product(p^e)) = Product(Gaussian_poly[e+n-1, e]p). - _Álvar Ibeas, Oct 31 2015

Extensions

Edited by Charles R Greathouse IV, Oct 28 2009

A346463 a(n) = 6 * GaussBinomial(2*n, 2, 2) / denominator(Bernoulli(2*n, 1)).

Original entry on oeis.org

0, 1, 7, 93, 2159, 15841, 6141, 44731051, 8421119, 86113647, 3331843885, 127479517837, 103104368637, 750599904340651, 82824819807611, 80500035008073, 36170086393773823, 49191317521302203051, 2460603943675971, 12592977287514948283051, 89351501819019263845
Offset: 0

Views

Author

Peter Luschny, Jul 19 2021

Keywords

Crossrefs

Programs

  • Maple
    a := n -> (4^n - 2)*(4^n - 1) / mul(i, i=select(isprime, map(i->i+1, numtheory[divisors] (2*n)))): seq(a(n), n = 0..20);
  • Mathematica
    Table[6 QBinomial[2 n, 2, 2] / Denominator[BernoulliB[2 n, 1]], {n, 0, 20}]

Formula

a(n) = (4^n - 2)*(4^n - 1)/Clausen(2*n, 1), where Clausen(n, k) = A160014(n, k).

A346464 a(n) = 6 * GaussBinomial(2*n, 2, 2) * Bernoulli(2*n, 1).

Original entry on oeis.org

0, 1, -7, 93, -2159, 79205, -4243431, 313117357, -30459187423, 3777547352949, -581776592603735, 108932905225448381, -24370170371013413967, 6419958293615735090053, -1967044830254804722091719, 693575524342402846796188365, -278846808098157253796358662591
Offset: 0

Views

Author

Peter Luschny, Jul 19 2021

Keywords

Crossrefs

Programs

  • Maple
    a := n -> `if`(n = 0, 0, -2*n*(4^n - 2)*(4^n - 1)*Zeta(1 - 2*n)):
    seq(a(n), n = 0..16);
  • Mathematica
    Table[6 QBinomial[2 n, 2, 2] BernoulliB[2 n, 1], {n, 0, 16}]

Formula

a(n) = -2*n*(4^n - 2)*(4^n - 1)*zeta(1 - 2*n) for n >= 1.

A006099 Gaussian binomial coefficient [ n, n/2 ] for q=2.

Original entry on oeis.org

1, 1, 3, 7, 35, 155, 1395, 11811, 200787, 3309747, 109221651, 3548836819, 230674393235, 14877590196755, 1919209135381395, 246614610741341843, 63379954960524853651, 16256896431763117598611, 8339787869494479328087443, 4274137206973266943778085267
Offset: 0

Views

Author

Keywords

References

  • J. Goldman and G.-C. Rota, The number of subspaces of a vector space, pp. 75-83 of W. T. Tutte, editor, Recent Progress in Combinatorics. Academic Press, NY, 1969.
  • I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p. 99.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Crossrefs

Cf. A065446.

Programs

  • Mathematica
    Table[QBinomial[n,Floor[n/2],2],{n,0,20}] (* Harvey P. Dale, Sep 07 2013 *)

Formula

a(n) ~ c * 2^(n^2/4), where c = 1 / QPochhammer[1/2, 1/2] = A065446 = 3.46274661945506361153795734292443116454... if n is even, and c = 2^(-1/4) / QPochhammer[1/2, 1/2] = 2^(-1/4) * A065446 = 2.911811219231681420726836976930855961516... if n is odd. - Vaclav Kotesovec, Jun 22 2014

Extensions

More terms from Harvey P. Dale, Sep 07 2013

A006102 Gaussian binomial coefficient [ n,4 ] for q=3.

Original entry on oeis.org

1, 121, 11011, 925771, 75913222, 6174066262, 500777836042, 40581331447162, 3287582741506063, 266307564861468823, 21571273555248777493, 1747282899667791058573, 141530177899268957392924, 11463951511551877750726204, 928580264181940191843785764, 75215006575885931519565302404
Offset: 4

Views

Author

Keywords

References

  • J. Goldman and G.-C. Rota, The number of subspaces of a vector space, pp. 75-83 of W. T. Tutte, editor, Recent Progress in Combinatorics. Academic Press, NY, 1969.
  • I. P. Goulden and D. M. Jackson, Combinatorial Enumeration. Wiley, NY, 1983, p. 99.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Crossrefs

Partial sums of A226804. - Christian Krause, Dec 26 2022

Programs

  • Magma
    r:=4; q:=3; [&*[(1-q^(n-i+1))/(1-q^i): i in [1..r]]: n in [r..20]]; // Vincenzo Librandi, Aug 02 2016
  • Maple
    A006102:=-1/((z-1)*(81*z-1)*(3*z-1)*(9*z-1)*(27*z-1)); # conjectured (correctly) by Simon Plouffe in his 1992 dissertation
  • Mathematica
    Table[QBinomial[n, 4, 3], {n, 4, 24}] (* Vincenzo Librandi, Aug 02 2016 *)
  • Sage
    [gaussian_binomial(n,4,3) for n in range(4,20)] # Zerinvary Lajos, May 25 2009
    
Previous Showing 41-50 of 79 results. Next