OFFSET
1,2
COMMENTS
It turns out that "...at least n..." and "...exactly n..." yield the same (and thus strictly increasing) sequence. - M. F. Hasler, Feb 02 2009
EXAMPLE
13^2=169 is the first square to contain exactly 3 different digits; 322^2=103684 is the first square to contain exactly 6 different digits.
PROG
(PARI) A054039(n, k=0) = { while( #Set(Vec(Str(k^2)))<n, k++); k } /* If "exactly n" would correspond to a different sequence, this would yield some term twice in a row. The optional 2nd arg can be used to find further terms with a given # of distinct digits. - M. F. Hasler, Feb 02 2009 */
CROSSREFS
KEYWORD
nonn,fini,full,base,easy
AUTHOR
Asher Auel, Feb 28 2000
EXTENSIONS
Minor rewording, added comment, keywords "easy,full" and PARI code M. F. Hasler, Feb 02 2009
STATUS
approved