OFFSET
1,19
COMMENTS
a(n)=0 for n=1,2,7,8,13,14,31,32,49,50,55,56,61,62...hence if a(n)=0, n odd it seems that a(n+1)=0. It seems also that if a(n)=0 (n odd ) then n == 1 mod 6 (converse doesn't hold).
PROG
(PARI) for(n=1, 70, print1(matdet(matrix(n, n, i, j, length(binary(j+i))%2)), ", "))
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Benoit Cloitre, Jun 09 2002
EXTENSIONS
Name corrected by Nathaniel Johnston, Sep 26 2011
STATUS
approved