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A214072 Least m>0 such that (2*n-1)!!+m and (2*n)!!-m are not relatively prime. 1
2, 8, 3, 3, 1, 3, 3, 3, 1, 3, 1, 3, 3, 3, 1, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 1, 3, 1, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
gcd(15+1,48-1) = 1, gcd(15+2,48-2) = 1, gcd(15+3,48-3) > 1, so that a(3) = 3.
MATHEMATICA
b[n_] := (2 n - 1)!!; c[n_] := (2 n)!!;
Table[m = 1; While[GCD[b[n] + m, c[n] - m] == 1, m++]; m, {n, 1, 140}]
CROSSREFS
Cf. A214054.
Sequence in context: A273692 A006085 A021357 * A016640 A321984 A083486
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 26 2012
STATUS
approved

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Last modified August 29 15:03 EDT 2024. Contains 375517 sequences. (Running on oeis4.)