A000823 Number of switching networks (see Harrison reference for precise definition). (Formerly M4428 N1872)

7, 46, 4336, 134281216, 288230380379570176, 2658455991569831764110243006194384896, 452312848583266388373324160190187140390789016525312000869601987902398529536

Offset

1,1

Comments

Number of equivalence classes with complementation of n variables on the domain and symmetric group of 2 variables operating on the range. - Sean A. Irvine, Jul 11 2011

Essentially the same sequence as A000231. - Sean A. Irvine, Jul 11 2011

References

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..7.

M. A. Harrison, On the number of classes of switching networks, J. Franklin Instit., 276 (1963), 313-327.

Index entries for sequences related to switching networks

Formula

a(n) = 2^(2^(n+1) - n - 1) + 2^(2^n) - 2^(2^n - n - 1). - Sean A. Irvine, Jul 11 2011 [Corrected by Sean A. Irvine, Dec 07 2023]

Mathematica

a[n_]:= 2^(2^(n+1) - n - 1) + 2^(2^n) - 2^(2^n - n - 1); Table[a[n], {n, 7}] (* James C. McMahon, Dec 09 2023 *)

Crossrefs

Sequence in context: A319601 A352693 A197754 * A036944 A068640 A089725

Adjacent sequences: A000820 A000821 A000822 * A000824 A000825 A000826

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Sean A. Irvine, Jul 10 2011

a(7) corrected by Sean A. Irvine, May 29 2013

Status

approved