OFFSET
1,1
COMMENTS
Number of equivalence classes with complementation of n variables on the domain and symmetric group of 3 variables operating on the range. - 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
M. A. Harrison, On the number of classes of switching networks, J. Franklin Instit., 276 (1963), 313-327.
FORMULA
Let b_n(r,s) = (2^(r*2^n) + (2^n-1)*2^(s*2^(n-1)))/2^n. Then, a(n) = (b_n(3,3) + 3*b(2,3) + 2*b(1,1))/6. - Sean A. Irvine, Jul 11 2011
MATHEMATICA
b[n_, r_, s_] := (2^(r*2^n) + (2^n - 1)*2^(s*2^(n - 1)))/2^n; a[n_] := (b[n, 3, 3] + 3*b[n, 2, 3] + 2*b[n, 1, 1])/6; Table[a[n], {n, 6}] (* James C. McMahon, Dec 07 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Jul 10 2011
STATUS
approved