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A214180 Least m>0 such that 2^n-m and 5^n-m are relatively prime. 3
1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 3, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 3, 2, 1, 2, 3, 3, 1, 2, 1, 2, 3, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 3, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 3, 2, 1, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(616) = 5.

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..1000

EXAMPLE

gcd(16-1,625-1) = 3, gcd(16-2,625-2) = 7, gcd(16-3,625-3) = 1, so a(4) = 3.

MATHEMATICA

Table[m = 1; While[GCD[2^n - m, 5^n - m] != 1, m++]; m, {n, 1, 140}]

CROSSREFS

Cf. A214074, A214708.

Sequence in context: A174532 A089242 A185894 * A184166 A029423 A184169

Adjacent sequences:  A214177 A214178 A214179 * A214181 A214182 A214183

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Jul 27 2012

STATUS

approved

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Last modified November 12 09:01 EST 2019. Contains 329052 sequences. (Running on oeis4.)