A184278 Number of distinct n X n toroidal 0..2 arrays.

3, 27, 2211, 2691711, 33891544611, 4169295457320267, 4883659780216684279491, 53651309692070594433108320631, 5474401089420219382077156686715199875, 5153775207320113310364632834595843483435609099, 44553974378043749018508590814287728257805180848046070883

Offset: 1

Author

R. H. Hardin, Jan 10 2011

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..40

Crossrefs

Diagonal of A184284.

Formula

a(n) = (1/(n^2)) * Sum_{c|n} Sum_{d|n} phi(c) * phi(d) * 3^(n^2/lcm(c,d)). - Andrew Howroyd, Sep 27 2017

Extensions

Terms a(6) and beyond from Andrew Howroyd, Sep 27 2017