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A214708 Least m>0 such that 4^n-m and 5^n-m are relatively prime. 2
1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(248) = 3.  Is every term < 4?

LINKS

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

EXAMPLE

gcd(256-1,625-1) = 3 and gcd(256-2, 625-2) = 1, so a(4) = 2.

MATHEMATICA

Table[m = 1; While[GCD[4^n - m, 5^n - m] != 1, m++]; m, {n, 1, 140}]

CROSSREFS

Cf. A214074, A214707.

Sequence in context: A070304 A275308 A233138 * A083952 A245225 A214860

Adjacent sequences:  A214705 A214706 A214707 * A214709 A214710 A214711

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Jul 27 2012

STATUS

approved

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Last modified April 20 02:06 EDT 2019. Contains 322291 sequences. (Running on oeis4.)