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.

A022172 Triangle of Gaussian binomial coefficients [ n,k ] for q = 8.

Original entry on oeis.org

1, 1, 1, 1, 9, 1, 1, 73, 73, 1, 1, 585, 4745, 585, 1, 1, 4681, 304265, 304265, 4681, 1, 1, 37449, 19477641, 156087945, 19477641, 37449, 1, 1, 299593, 1246606473, 79936505481, 79936505481, 1246606473, 299593, 1
Offset: 0

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Keywords

Examples

			Triangle begins:
  1;
  1,      1;
  1,      9,          1;
  1,     73,         73,           1;
  1,    585,       4745,         585,           1;
  1,   4681,     304265,      304265,        4681,          1;
  1,  37449,   19477641,   156087945,    19477641,      37449,      1;
  1, 299593, 1246606473, 79936505481, 79936505481, 1246606473, 299593, 1;
		

References

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

Crossrefs

Cf. A023001 (k=1), A022242 (k=2).

Programs

  • Maple
    A027876 := proc(n)
        mul(8^i-1,i=1..n) ;
    end proc:
    A022172 := proc(n,m)
        A027876(n)/A027876(m)/A027876(n-m) ;
    end proc: # R. J. Mathar, Jul 19 2017
  • Mathematica
    a027878[n_]:=Times@@ Table[8^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 *)
    Table[QBinomial[n,k,8], {n,0,10}, {k,0,n}]//Flatten (* or *) q:= 8; 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=8; T(n,k) = if(k==0,1, if (k==n, 1, if (k<0 || nG. C. Greubel, May 27 2018
  • Python
    from operator import mul
    def a027878(n): return 1 if n==0 else reduce(mul, [8**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
    

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) = 8^j - 1. - Seiichi Manyama, May 09 2025