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.

A022619 Triangle T(n,k)of numbers of asymmetric Boolean functions of n variables with exactly k = 0..2^n nonzero values (atoms) under action of complementing group C(n,2).

Original entry on oeis.org

0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 7, 7, 7, 0, 1, 0, 0, 1, 0, 35, 105, 273, 448, 715, 750, 715, 448, 273, 105, 35, 0, 1, 0, 0, 1, 0, 155, 1085, 6293, 27776, 105183, 327050, 876525, 2011776, 4032015, 7048811, 10855425, 14721280, 17678835, 18771864
Offset: 1

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Author

Vladeta Jovovic, Jul 13 2000

Keywords

Examples

			Triangle begins:
  [0,1,0],
  [0,1,0,1,0],
  [0,1,0,7,7,7,0,1,0],
  ...;
T(5,k) = coefficient of x^k in (1/32)*((1+x)^32-31*(1+x^2)^16+310*(1+x^4)^8-1240*(1+x^8)^4+1984*(1+x^16)^2-1024*(1+x^32)),k = 0..32.
		

Crossrefs

Row sums give A051502.
Cf. A054724.

Programs

  • Mathematica
    T[n_,0]:=0; T[n_, k_] := (1/2^n)*Coefficient[Sum[(-1)^j*2^(Binomial[j, 2])* QBinomial[n, j, 2]*(1 + x^(2^j))^(2^(n - j)), {j, 0, n}], x^k];
    Table[T[n, k], {n, 1, 5}, {k, 0, 2^n}] // Flatten (* G. C. Greubel, Feb 15 2018 *)

Formula

T(n, k) = coefficient of x^k in (1/2^n)*Sum_{j = 0..n} (-1)^j*2^C(j, 2)*[n, j]*(1+x^(2^j))^(2^(n-j)), where [n, j] is Gaussian 2-binomial coefficient; k = 0..2^n.