A184267 Number of distinct n X 5 toroidal binary arrays.

8, 108, 2192, 52488, 1342208, 35792568, 981706832, 27487816992, 781874936816, 22517998808448, 655069036708592, 19215358428046176, 567592125344909792, 16865594582168158776, 503719091506096394752, 15111572745196608608736, 455125014443154512836736

Offset: 1

Author

R. H. Hardin, Jan 10 2011

Keywords

• nonn

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 1..660
• S. N. Ethier, Counting toroidal binary arrays, arXiv preprint arXiv:1301.2352, 2013 and J. Int. Seq. 16 (2013) #13.4.7 .

Crossrefs

Column 5 of A184271.

Programs

Maple

with(numtheory):
a:= n-> add(add(phi(c)*phi(d) *2^(5*n/ilcm(c, d)),
        d=divisors(n)), c=[1,5])/(5*n):
seq(a(n), n=1..25);  # Alois P. Heinz, Aug 25 2012

Formula

a(n) ~ 32^n / (5*n). - Vaclav Kotesovec, Sep 04 2014

Extensions

More terms from Alois P. Heinz, Aug 25 2012