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A184266
Number of distinct n X 4 toroidal binary arrays.
2
6, 40, 352, 4156, 52488, 699600, 9587580, 134223976, 1908881900, 27487869472, 399822505524, 5864063067176, 86607686432616, 1286742765058960, 19215358428046176, 288230376353050696, 4340410370537249376, 65588423376053309360, 994182417449857925988
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OFFSET
1,1
LINKS
Vaclav Kotesovec,
Table of n, a(n) for n = 1..820
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) ~ 2^(4*n-2) / n. -
Vaclav Kotesovec
, Sep 04 2014
MAPLE
with(numtheory):
a:= n-> add(add(phi(c)*phi(d) *2^(4*n/ilcm(c, d)),
d=divisors(n)), c=[1, 2, 4])/(4*n):
seq(a(n), n=1..30); #
Alois P. Heinz
, Aug 25 2012
CROSSREFS
Column 4 of
A184271
.
Sequence in context:
A341587
A006387
A014481
*
A000683
A352357
A143342
Adjacent sequences:
A184263
A184264
A184265
*
A184267
A184268
A184269
KEYWORD
nonn
AUTHOR
R. H. Hardin
, Jan 10 2011
EXTENSIONS
More terms from
Alois P. Heinz
, Aug 25 2012
STATUS
approved
