OFFSET
1,3
COMMENTS
Fixed-point free permutations such that each row in the difference table consists of pairwise distinct elements (see example).
LINKS
Scott Rickard, costasarrays.org (information and papers about Costas arrays).
EXAMPLE
The permutation (9, 8, 1, 6, 3, 7, 2, 4, 5) is a derangement and corresponds to a Costas array:
9 8 1 6 3 7 2 4 5 (Permutation: p(1), p(2), p(3), ..., p(n) )
-1 -7 5 -3 4 -5 2 1 (step-1 differences: p(2)-p(1), p(3)-p(2), ... )
-8 -2 2 1 -1 -3 3 (step-2 differences: p(3)-p(1), p(4)-p(2), ... )
-3 -5 6 -4 1 -2 (step-3 differences: p(4)-p(1), p(5)-p(2), ... )
-6 -1 1 -2 2 ( etc. )
-2 -6 3 -1
-7 -4 4
-5 -3
-4
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Joerg Arndt, Jun 08 2012
STATUS
approved