A184265 Number of distinct n X 3 toroidal binary arrays.

4, 14, 64, 352, 2192, 14624, 99880, 699252, 4971184, 35792568, 260301176, 1908882592, 14096303344, 104715443852, 781874941184, 5864062367252, 44152937528384, 333599974922264, 2528336632928152, 19215358428046176, 146402730743992960, 1117984489446008100

Offset

1,1

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..1000

S. N. Ethier, Counting toroidal binary arrays, arXiv preprint arXiv:1301.2352, 2013 and J. Int. Seq. 16 (2013) #13.4.7 .

Formula

a(n) ~ 8^n / (3*n). - Vaclav Kotesovec, Sep 04 2014

Maple

with(numtheory):
a:= n-> add(add(phi(c)*phi(d) *2^(3*n/ilcm(c, d)),
        d=divisors(n)), c=[1, 3])/(3*n):
seq(a(n), n=1..30);  # Alois P. Heinz, Aug 25 2012

Crossrefs

Column 3 of A184271.

Sequence in context: A356004 A154407 A222467 * A020041 A081891 A119857

Adjacent sequences: A184262 A184263 A184264 * A184266 A184267 A184268

Keyword

nonn

Author

R. H. Hardin, Jan 10 2011

Extensions

More terms from Alois P. Heinz, Aug 25 2012

Status

approved