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 1-7 of 7 results.

A022168 Triangle of Gaussian binomial coefficients [ n,k ] for q = 4.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 1, 21, 21, 1, 1, 85, 357, 85, 1, 1, 341, 5797, 5797, 341, 1, 1, 1365, 93093, 376805, 93093, 1365, 1, 1, 5461, 1490853, 24208613, 24208613, 1490853, 5461, 1, 1, 21845, 23859109, 1550842085, 6221613541
Offset: 0

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Author

Keywords

Comments

The coefficients of the matrix inverse are apparently given by T^(-1)(n,k) = (-1)^n*A157784(n,k). - R. J. Mathar, Mar 12 2013

Examples

			Triangle begins:
  1;
  1,    1;
  1,    5,       1;
  1,   21,      21,        1;
  1,   85,     357,       85,        1;
  1,  341,    5797,     5797,      341,       1;
  1, 1365,   93093,   376805,    93093,    1365,    1;
  1, 5461, 1490853, 24208613, 24208613, 1490853, 5461, 1;
		

References

  • F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier-North Holland, 1978, p. 698.

Crossrefs

Cf. A006118 (row sums), A002450 (k=1), A006105 (k=2), A006106 (k=3).

Programs

  • Maple
    A022168 := proc(n,m)
            A027637(n)/A027637(n-m)/A027637(m) ;
    end proc: # R. J. Mathar, Nov 14 2011
  • Mathematica
    gaussianBinom[n_, k_, q_] := Product[q^i - 1, {i, n}]/Product[q^j - 1, {j, n - k}]/Product[q^l - 1, {l, k}]; Column[Table[gaussianBinom[n, k, 4], {n, 0, 8}, {k, 0, n}], Center] (* Alonso del Arte, Nov 14 2011 *)
    Table[QBinomial[n,k,4], {n,0,10}, {k,0,n}]//Flatten (* or *) q:= 4; T[n_, 0]:= 1; T[n_,n_]:= 1; T[n_,k_]:= T[n,k] = If[k < 0 || n < k, 0, T[n-1, k -1] +q^k*T[n-1,k]]; Table[T[n,k], {n,0,10}, {k,0,n}] // Flatten  (* G. C. Greubel, May 27 2018 *)
  • PARI
    {q=4; T(n,k) = if(k==0,1, if (k==n, 1, if (k<0 || nG. C. Greubel, May 27 2018

Formula

T(n,k) = T(n-1,k-1) + q^k * T(n-1,k). - Peter A. Lawrence, Jul 13 2017
G.f. of column k: x^k * exp( Sum_{j>=1} f((k+1)*j)/f(j) * x^j/j ), where f(j) = 4^j - 1. - Seiichi Manyama, May 09 2025

A015195 Sum of Gaussian binomial coefficients for q=9.

Original entry on oeis.org

1, 2, 12, 184, 9104, 1225248, 540023488, 652225844096, 2584219514040576, 28081351726592246272, 1001235747932175990213632, 97915621602690773814148184064, 31420034518763282871588038742544384, 27654326463468067495668136467306727743488
Offset: 0

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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.
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Crossrefs

Row sums of triangle A022173.

Programs

  • Mathematica
    Total/@Table[QBinomial[n, m, 9], {n, 0, 20}, {m, 0, n}] (* Vincenzo Librandi, Nov 01 2012 *)
    Flatten[{1,RecurrenceTable[{a[n]==2*a[n-1]+(9^(n-1)-1)*a[n-2],a[0]==1,a[1]==2},a,{n,1,15}]}] (* Vaclav Kotesovec, Aug 21 2013 *)

Formula

a(n) = 2*a(n-1)+(9^(n-1)-1)*a(n-2), (Goldman + Rota, 1969). - Vaclav Kotesovec, Aug 21 2013
a(n) ~ c * 9^(n^2/4), where c = EllipticTheta[3,0,1/9]/QPochhammer[1/9,1/9] = 1.3946866902389... if n is even and c = EllipticTheta[2,0,1/9]/QPochhammer[1/9,1/9] = 1.333574200539... if n is odd. - Vaclav Kotesovec, Aug 21 2013

A015196 Sum of Gaussian binomial coefficients for q=10.

Original entry on oeis.org

1, 2, 13, 224, 13435, 2266646, 1348019857, 2269339773068, 13484735901526279, 226960944509263279490, 13485189809930561625032701, 2269636415245291711513986785912, 1348523520252401463276762566348539123
Offset: 0

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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.
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Crossrefs

Row sums of triangle A022174.

Programs

  • Mathematica
    Total/@Table[QBinomial[n, m, 10], {n, 0, 20}, {m, 0, n}] (* Vincenzo Librandi, Nov 01 2012 *)
    Flatten[{1,RecurrenceTable[{a[n]==2*a[n-1]+(10^(n-1)-1)*a[n-2],a[0]==1,a[1]==2},a,{n,1,15}]}] (* Vaclav Kotesovec, Aug 21 2013 *)

Formula

a(n) = 2*a(n-1)+(10^(n-1)-1)*a(n-2), (Goldman + Rota, 1969). - Vaclav Kotesovec, Aug 21 2013
a(n) ~ c * 10^(n^2/4), where c = EllipticTheta[3,0,1/10]/QPochhammer[1/10,1/10] = 1.348524024616... if n is even and c = EllipticTheta[2,0,1/10]/QPochhammer[1/10,1/10] = 1.2763120346269... if n is odd. - Vaclav Kotesovec, Aug 21 2013

A228465 Recurrence a(n) = a(n-1) + 2^n*a(n-2) with a(0)=0, a(1)=1.

Original entry on oeis.org

0, 1, 1, 9, 25, 313, 1913, 41977, 531705, 22023929, 566489849, 45671496441, 2366013917945, 376506912762617, 39141278944373497, 12376519796349807353, 2577539376694811306745, 1624792742123856760679161, 677311275106408471956040441, 852536648457739021814912002809
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 22 2013

Keywords

Comments

Generally (if p>0, q>1), recurrence a(n) = b*a(n-1) + (p*q^n+d)*a(n-2), a(n) is asymptotic to c*q^(n^2/4)*(p*q)^(n/2), where c is for fixed parameters b, p, d, q, a(0), a(1) constant, independent on n.

Crossrefs

Programs

  • Magma
    [n le 2 select (n-1) else Self(n-1)+Self(n-2)*2^(n-1): n in [1..20]]; // Vincenzo Librandi, Aug 23 2013
    
  • Mathematica
    RecurrenceTable[{a[n]==a[n-1]+2^n*a[n-2],a[0]==0,a[1]==1},a,{n,0,20}]
    (* Alternative: *)
    a[n_] := Sum[2^(k^2-1) QBinomial[n - k , k - 1, 2], {k, 1, n}];
    Table[a[n], {n, 0, 19}] (* After Vladimir Kruchinin. Peter Luschny, Jan 20 2020 *)
  • SageMath
    def a(n):
        return sum(2^(k^2 - 1)*q_binomial(n-k , k-1, 2) for k in (1..n))
    print([a(n) for n in range(20)]) # Peter Luschny, Jan 20 2020

Formula

a(n) ~ c * 2^(n^2/4 + n/2), where c = 0.548441579870783378573455400152590154... if n is even and c = 0.800417244834941368929416800341853541... if n is odd.
a(n) = Sum_{k=1..floor(n/2+1/2)} qbinomial(n-k,k-1)*2^(k^2-1), where q-binomial is triangle A022166, that is, with q=2. - Vladimir Kruchinin, Jan 20 2020

A015197 Sum of Gaussian binomial coefficients for q=11.

Original entry on oeis.org

1, 2, 14, 268, 19156, 3961832, 3092997464, 7024809092848, 60287817008722576, 1505950784990730735392, 142158530752430089391520224, 39060769254069395008311334483648, 40559566021977397260316290099710383936
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.
  • M. Sved, Gaussians and binomials, Ars. Combinatoria, 17A (1984), 325-351.

Crossrefs

Programs

  • Mathematica
    Total/@Table[QBinomial[n, m, 11], {n, 0, 20}, {m, 0, n}] (* Vincenzo Librandi, Nov 02 2012 *)
    Flatten[{1,RecurrenceTable[{a[n]==2*a[n-1]+(11^(n-1)-1)*a[n-2],a[0]==1,a[1]==2},a,{n,1,15}]}] (* Vaclav Kotesovec, Aug 21 2013 *)

Formula

a(n) = 2*a(n-1)+(11^(n-1)-1)*a(n-2), (Goldman + Rota, 1969). - Vaclav Kotesovec, Aug 21 2013
a(n) ~ c * 11^(n^2/4), where c = EllipticTheta[3,0,1/11]/QPochhammer[1/11,1/11] = 1.312069129398... if n is even and c = EllipticTheta[2,0,1/11]/QPochhammer[1/11,1/11] = 1.2291712170215... if n is odd. - Vaclav Kotesovec, Aug 21 2013

A174528 Triangle T(n,m) = 2*A022168(n,m) - binomial(n, m), 0 <= m <= n, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 8, 1, 1, 39, 39, 1, 1, 166, 708, 166, 1, 1, 677, 11584, 11584, 677, 1, 1, 2724, 186171, 753590, 186171, 2724, 1, 1, 10915, 2981685, 48417191, 48417191, 2981685, 10915, 1, 1, 43682, 47718190, 3101684114, 12443227012, 3101684114, 47718190
Offset: 0

Views

Author

Roger L. Bagula and Gary W. Adamson, Mar 21 2010

Keywords

Comments

Row sums are 1, 2, 10, 80, 1042, 24524, 1131382, 102819584, 18742118986, 6775774063892, 4926666912583390, ... = 2*A006118(n) - 2^n.
This triangle essentially compares a Gaussian binomial equivalent to Pascal's triangle and Pascal's triangle itself. - Alonso del Arte, Nov 14 2011

Examples

			Triangle begins
  1;
  1,     1;
  1,     8,        1;
  1,    39,       39,          1;
  1,   166,      708,        166,           1;
  1,   677,    11584,      11584,         677,          1;
  1,  2724,   186171,     753590,      186171,       2724,        1;
  1, 10915,  2981685,   48417191,    48417191,    2981685,    10915,     1;
  1, 43682, 47718190, 3101684114, 12443227012, 3101684114, 47718190, 43682, 1;
		

Programs

  • Maple
    A174528 := proc(n,k)
            2*A022168(n,k)-binomial(n,k) ;
    end proc:
    seq(seq(A174528(n,m),m=0..n),n=0..10) ; # R. J. Mathar, Nov 14 2011
  • Mathematica
    c[n_, q_] = Product[1 - q^i, {i, 1, n}];
    t[n_, m_, q_] = 2*c[n, q]/(c[m, q]*c[n - m, q]) - Binomial[n, m];
    Table[Flatten[Table[Table[t[n, m, q], {m, 0, n}], {n, 0, 10}]], {q, 2, 12}]
    (* alternate program *)
    (* First run the program for A022168 to define gaussianBinom *)
    Column[Table[2gaussianBinom[n, k, 4] - Binomial[n, k], {n, 0, 8}, {k, 0, n}], Center] (* Alonso del Arte, Nov 14 2011 *)

A348103 a(n) is the number of vector subspaces in (F_4)^n, counted up to coordinate permutation.

Original entry on oeis.org

1, 2, 5, 16, 57, 262, 1746, 18304, 340435, 11805530, 779700089, 96708911116, 22633062447491, 9857264291668086
Offset: 0

Views

Author

Álvar Ibeas, Sep 30 2021

Keywords

Crossrefs

Row sums of A347971. Cf. A006118.
Showing 1-7 of 7 results.