

A124068


Fixed points for operation of repeatedly replacing a number with the sum of the seventh power of its digits.


9




OFFSET

1,3


COMMENTS

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 ddigit number n >= 10^(d1), the sum of 7th powers of its digits is <= 9^7*d, therefore these numbers cannot exceed 41205040.  M. F. Hasler, Apr 12 2015


LINKS



EXAMPLE

1741725 = 1^7 + 7^7 + 4^7 + 1^7 + 7^7 + 2^7 + 5^7.


PROG

(PARI) isok(n) = my(d = digits(n)); sum(k=1, #d, d[k]^7) == n; \\ Michel Marcus, Feb 21 2015


CROSSREFS



KEYWORD

base,fini,full,nonn


AUTHOR



STATUS

approved



