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A054039 a(n)^2 is the least square to contain n different decimal digits. 12
0, 4, 13, 32, 113, 322, 1017, 3206, 10124, 32043 (list; graph; refs; listen; history; text; internal format)
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

LINKS

Table of n, a(n) for n=1..10.

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

Cf. A016069, A054031, A054032, A054033, A054034, A054035, A054036, A054037, A054038.

Sequence in context: A173277 A036420 A266094 * A302082 A124669 A036894

Adjacent sequences:  A054036 A054037 A054038 * A054040 A054041 A054042

KEYWORD

nonn,fini,full,base,easy

AUTHOR

Asher Auel (asher.auel(AT)reed.edu) Feb 28 2000

EXTENSIONS

Minor rewording, added comment, keywords "easy,full" and PARI code M. F. Hasler, Feb 02 2009

STATUS

approved

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Last modified February 23 18:54 EST 2019. Contains 320438 sequences. (Running on oeis4.)