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Search: id:A112321
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| A112321 |
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Least n-digit number such that its square is exclusionary, or 0 if no such number exists. |
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+0
4
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OFFSET
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1,1
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COMMENT
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m has an exclusionary square if m consists of distict digits and m^2 is made up only of digits not appearing in m.
a(10) = 0 since 10-digit numbers either use all digits or at least one digit more than once; a(n) = 0 for n > 10 since numbers with more than 10 digits use at least one digit more than once.
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REFERENCES
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H. Ibstedt, Solution to Problem 2623 "Exclusionary Powers", Journal of Recreational Mathematics pp. 346-9 Vol. 32 no.4 2003-4 Baywood NY.
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CROSSREFS
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Cf. A112322 (corresponding squares), A110815.
Adjacent sequences: A112318 A112319 A112320 this_sequence A112322 A112323 A112324
Sequence in context: A110815 A074624 A126037 this_sequence A003419 A126109 A046909
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KEYWORD
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nonn,base,fini
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com) and Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Sep 08 2005
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