OFFSET
0,2
COMMENTS
Burnside's orbit-counting lemma
LINKS
María Merino, Table of n, a(n) for n = 0..34
M. Merino and I. Unanue, Counting squared grid patterns with Pólya Theory, EKAIA, 34 (2018), 289-316 (in Basque).
FORMULA
a(n) = (1/8)*(7^(n^2) + 2*7^(n^2/4) + 3*7^(n^2/2) + 2*7^((n^2 + n)/2)) if n is even;
a(n) = (1/8)*(7^(n^2) + 2*7^((n^2 + 3)/4) + 7^((n^2 + 1)/2) + 4*7^((n^2 + n)/2)) if n is odd.
CROSSREFS
KEYWORD
nonn
AUTHOR
María Merino, Imanol Unanue, Yosu Yurramendi, May 08 2017
STATUS
approved