OFFSET
1,4
COMMENTS
LINKS
Wikipedia, Sierpiński carpet
EXAMPLE
The first pairs are:
(1, 1),
(1, 4), (4, 1),
(3, 3),
(3, 4), (4, 3),
(1, 7), (3, 5), (4, 4), (5, 3), (7, 1),
(4, 5), (5, 4),
(5, 5),
(1, 10), (4, 7), (7, 4), (10, 1),
...
PROG
(PARI) is(i, j) = { while (i && j, if (i%3==1 && j%3==1, return (0), i\=3; j\=3; ); ); return (1); }
row(ij) = apply (i -> [i, ij-i], select(i -> !is(i, ij-i), [0..ij]))
CROSSREFS
KEYWORD
nonn,tabf,base
AUTHOR
Rémy Sigrist, Apr 16 2023
STATUS
approved