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Search: id:A101335
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| A101335 |
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n-digit numbers not equal to sum of k-th powers of their digits (A005188), but equal to the sum of k-th powers of their digits nested once. |
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+0
1
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| 136, 244, 2178, 6514, 58618, 76438, 2755907, 6586433, 8139850, 9057586
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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Ken Follett, Code to Zero, Dutton, NY 2000, p. 84.
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FORMULA
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Let n = d_1 d_2 ... d_k in base 10; then f(n) = Sum_{i=1..k} d_i^k. a(n) # f(a(n)) but a(n) = f(f(a(n))).
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EXAMPLE
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1^3+3^3+6^3=244 => 2^3+4^3+4^3=136.
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MATHEMATICA
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f[n_] := Plus @@ (IntegerDigits[n]^Floor[Log[10, n] + 1]); Do[ lst = NestList[f, n, 2]; If[lst[[1]] == lst[[3]] != lst[[2]], Print[n]], {n, 110000000}] (from Robert G. Wilson v (rgwv(AT)rgwv.com), May 21 2005)
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CROSSREFS
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Cf. A005188.
Adjacent sequences: A101332 A101333 A101334 this_sequence A101336 A101337 A101338
Sequence in context: A072889 A157714 A165337 this_sequence A098215 A116223 A124241
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KEYWORD
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nonn,base
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AUTHOR
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Allyson A. Wilson (Foxtail(AT)southwind.net), May 04 2005
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