A124068 Fixed points for operation of repeatedly replacing a number with the sum of the seventh power of its digits.

0, 1, 1741725, 4210818, 9800817, 9926315, 14459929

Offset: 1

Author

Sébastien Dumortier, Nov 05 2006

Keywords

• base
• fini
• full
• nonn

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 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

Examples

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

Crossrefs

Cf. A046197, A052455, A052464, A124069, A226970, A003321.

Programs

PARI

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

PARI

for(n=0,41205040,A123253(n)==n&&print1(n",")) \\ M. F. Hasler, Apr 12 2015