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 1-2 of 2 results.

A022174 Triangle of Gaussian binomial coefficients [ n,k ] for q = 10.

Original entry on oeis.org

1, 1, 1, 1, 11, 1, 1, 111, 111, 1, 1, 1111, 11211, 1111, 1, 1, 11111, 1122211, 1122211, 11111, 1, 1, 111111, 112232211, 1123333211, 112232211, 111111, 1, 1, 1111111, 11223332211, 1123445443211, 1123445443211, 11223332211, 1111111, 1
Offset: 0

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Examples

			Triangle begins:
  1;
  1,       1;
  1,      11,           1;
  1,     111,         111,             1;
  1,    1111,       11211,          1111,             1;
  1,   11111,     1122211,       1122211,         11111,           1;
  1,  111111,   112232211,    1123333211,     112232211,      111111,       1;
  1, 1111111, 11223332211, 1123445443211, 1123445443211, 11223332211, 1111111, 1;
		

References

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

Crossrefs

Row sums give A015196.

Programs

  • Maple
    A027878 := proc(n)
        mul(10^i-1,i=1..n) ;
    end proc:
    A022174 := proc(n,m)
        A027878(n)/A027878(m)/A027878(n-m) ;
    end proc:# R. J. Mathar, Jul 19 2017
  • Mathematica
    a027878[n_]:=Times@@ Table[10^i - 1, {i, n}]; T[n_, m_]:=a027878[n]/( a027878[m] a027878[n - m]); Table[T[n, m], {n, 0, 10}, {m, 0, n}]//Flatten (* Indranil Ghosh, Jul 20 2017, after Maple code *)
    Table[QBinomial[n,k,10], {n,0,10}, {k,0,n}]//Flatten (* or *) q:= 10; 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 28 2018 *)
  • PARI
    {q=10; T(n,k) = if(k==0,1, if (k==n, 1, if (k<0 || nG. C. Greubel, May 28 2018
  • Python
    from operator import mul
    def a027878(n): return 1 if n==0 else reduce(mul, [10**i - 1 for i in range(1, n + 1)])
    def T(n, m): return a027878(n)/(a027878(m)*a027878(n - m))
    for n in range(11): print([T(n, m) for m in range(n + 1)]) # Indranil Ghosh, Jul 20 2017, after Maple code
    

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) = 10^j - 1. - Seiichi Manyama, May 09 2025

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

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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
Showing 1-2 of 2 results.