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A214074 Least m>0 such that 2^n-m and 3^n-m are relatively prime. 5
1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 2, 2, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Conjecture: a(n) = 3 if and only if n = 330*k-209 for some k>=1.

LINKS

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

EXAMPLE

gcd(64-1,729-1) = 7 and gcd(64-2,729-2) = 1, so a(6) = 2.

MATHEMATICA

Table[m = 1; While[GCD[2^n - m, 3^n - m] != 1, m++]; m, {n, 1, 140}]

CROSSREFS

Cf. A214180.

Sequence in context: A095772 A305392 A175301 * A003640 A107459 A087976

Adjacent sequences:  A214071 A214072 A214073 * A214075 A214076 A214077

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Jul 27 2012

STATUS

approved

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Last modified April 16 05:26 EDT 2021. Contains 343030 sequences. (Running on oeis4.)