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A086683 Number of n X n {-1,0,1} matrices modulo cyclic permutations of the rows. 1
1, 3, 45, 6579, 10763361, 169457722083, 25015772614247325, 34185618461516789943315, 429210477536564292209765507601, 49269609804781974438694405096704997875, 51537752073201133103646184766360896456864366605, 490093718158481239203594498957165010835856989328505008243 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..40

FORMULA

a(n) = (1/n)*Sum_{ d divides n } phi(d)*3^(n^2/d) for n > 0.

PROG

(PARI) a(n) = if(n<1, n==0, sumdiv(n, d, eulerphi(d)*3^(n^2/d))/n);

CROSSREFS

Cf. A086675, A060336.

Sequence in context: A229415 A265621 A124488 * A155203 A183131 A037105

Adjacent sequences:  A086680 A086681 A086682 * A086684 A086685 A086686

KEYWORD

nonn

AUTHOR

Yuval Dekel (dekelyuval(AT)hotmail.com), Jul 28 2003

EXTENSIONS

a(0)=1 prepended and terms a(7) and beyond from Andrew Howroyd, Jul 08 2018

STATUS

approved

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Last modified July 25 02:57 EDT 2021. Contains 346282 sequences. (Running on oeis4.)