OFFSET
1,2
EXAMPLE
a(4) = 4567 because 4567 is squarefree, while 4, 45 and 456 are not.
a(5) = 890 because 89 would cause a(6) to have a leading 0.
PROG
(PARI) used = matrix(9, 60); x = 1; for (n = 1, 80, num = x; s = x; d = 1; while (used[s, d] || !issquarefree(num) || x == 9, x = (x + 1)%10; num = 10*num + x; d++); print1(num, ", "); used[s, d] = 1; x++); \\ David Wasserman, Feb 14 2005
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Jul 14 2003
EXTENSIONS
Corrected and extended by David Wasserman, Feb 14 2005
STATUS
approved