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A016070
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Numbers n such that n^2 contains exactly 2 different digits, excluding 10^m, 2*10^m, 3*10^m.
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5
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4, 5, 6, 7, 8, 9, 11, 12, 15, 21, 22, 26, 38, 88, 109, 173, 212, 235, 264, 3114, 81619
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| A043537(a(n)) = 2. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 05 2010]
No other terms below 3.16*10^20 (derived from A018884).
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REFERENCES
| J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 109, p. 38, Ellipses, Paris 2008.
R. K. Guy, Unsolved Problems in Number Theory, F24.
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LINKS
| Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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CROSSREFS
| Cf. A016069, A018884, A018885.
Sequence in context: A189817 A173888 A120181 * A047569 A039062 A067187
Adjacent sequences: A016067 A016068 A016069 * A016071 A016072 A016073
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KEYWORD
| nonn,nice,base,more,hard
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com)
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