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Search: id:A054039
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| A054039 |
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a(n)^2 is the least square to contain n different decimal digits. |
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+0
9
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OFFSET
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1,2
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COMMENT
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It turns out that "...at least n..." and "...exactly n..." yield the same (and thus strictly increasing) sequence. - M. F. Hasler, Feb 02 2009
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EXAMPLE
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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.
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PROGRAM
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(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 */
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CROSSREFS
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Cf. A016069, A054031, A054032, A054033, A054034, A054035, A054036, A054037, A054038.
Sequence in context: A051912 A060099 A036420 this_sequence A124669 A036894 A135859
Adjacent sequences: A054036 A054037 A054038 this_sequence A054040 A054041 A054042
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KEYWORD
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nonn,fini,full,base,easy
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AUTHOR
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Asher Auel (asher.auel(AT)reed.edu) Feb 28 2000
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EXTENSIONS
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Minor rewording, added comment, keywords "easy,full" and PARI code M. F. Hasler (MHasler(AT)univ-ag.fr), Feb 02 2009
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