OFFSET
0,3
EXAMPLE
a(3) = 128:
[0, 1, 2;
4, 6, 8;
3, 5, 7]
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Stefano Spezia, Nov 18 2022
EXTENSIONS
a(4)-a(6) from Hugo Pfoertner, Nov 19 2022
STATUS
approved