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A124068
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Fixed points for operation of repeatedly replacing a number with the sum of the seventh power of its digits.
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9
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OFFSET
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1,3
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COMMENTS
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The sequence "Fixed points for operation of repeatedly replacing a number by the sum of the sixth power of its digits" has just 3 terms: 0, 1, and 548834.
For a d-digit number n >= 10^(d-1), the sum of 7th powers of its digits is <= 9^7*d, therefore these numbers cannot exceed 41205040. - M. F. Hasler, Apr 12 2015
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LINKS
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EXAMPLE
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1741725 = 1^7 + 7^7 + 4^7 + 1^7 + 7^7 + 2^7 + 5^7.
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PROG
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(PARI) isok(n) = my(d = digits(n)); sum(k=1, #d, d[k]^7) == n; \\ Michel Marcus, Feb 21 2015
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CROSSREFS
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KEYWORD
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base,fini,full,nonn
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AUTHOR
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STATUS
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approved
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