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A115026 Limiting value of n under iteration of "sum of the digits raised to the power of the number of digits of n" (A101337). 0
1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 5, 1, 370, 370, 370, 370, 370, 1, 4, 5, 8, 1, 4, 370, 370, 370, 1, 370, 9, 1, 1, 370, 370, 370, 370, 370, 370, 370, 370, 370, 4, 370, 1, 370, 370, 370, 370, 1, 370, 370, 370, 370, 370, 370, 370, 370, 370, 160, 370, 370, 370, 370, 370, 370 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Iterate A101337 starting at n until reaching a constant value (like 370) or a cycle (like 160, 217, 352, 160...). In the latter case a(n) takes the smallest value in the cycle (e.g. a(59) = 160). Since k*9^k < 10^k for all k>34, then each number n is guaranteed to yield a smaller number a(n) if n > 10^34, so every number reaches a constant or a cycle under this sequence.

LINKS

Table of n, a(n) for n=1..65.

EXAMPLE

E.g. a(89)=370 since:

89 (2 digits): 8^2 + 9^2 = 145

145 (3 digits): 1^3 + 4^3 + 5^3 = 190

190 (3 digits): 1^3 + 9^3 + 0^3 = 730

730 (3 digits): 7^3 + 3^3 + 0^3 = 370

370 (3 digits): 3^3 + 7^3 + 0^3 = 370...etc

So a(89) = 370 since 370 is a constant value under this series.

CROSSREFS

Cf. A101337.

Sequence in context: A080463 A209685 A114570 * A101337 A135208 A156207

Adjacent sequences:  A115023 A115024 A115025 * A115027 A115028 A115029

KEYWORD

nonn,base

AUTHOR

Sergio Pimentel, Feb 24 2006

STATUS

approved

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Last modified September 30 08:07 EDT 2014. Contains 247419 sequences.