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A214721 Least m>0 such that 2*n+1+m and n-m are not relatively prime. 1
1, 2, 1, 4, 1, 6, 1, 3, 1, 10, 1, 12, 1, 14, 1, 2, 1, 3, 1, 20, 1, 22, 1, 24, 1, 26, 1, 3, 1, 2, 1, 32, 1, 34, 1, 36, 1, 3, 1, 7, 1, 42, 1, 2, 1, 46, 1, 3, 1, 50, 1, 52, 1, 54, 1, 4, 1, 2, 1, 60, 1, 7, 1, 64, 1, 66, 1, 3, 1, 70, 1, 2, 1, 74, 1, 76, 1, 3, 1, 80, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

EXAMPLE

gcd(17,7) = 1, gcd(19,6) = 1, gcd(20,5) = 5, so a(8) = 3.

MATHEMATICA

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

CROSSREFS

Cf. A214060.

Sequence in context: A076512 A128707 A257022 * A324384 A329641 A329638

Adjacent sequences:  A214718 A214719 A214720 * A214722 A214723 A214724

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Jul 28 2012

STATUS

approved

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Last modified May 27 21:52 EDT 2020. Contains 334671 sequences. (Running on oeis4.)