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A214054
Least m>0 such that n!!+m and n-m have a common divisor > 1.
4
1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1
OFFSET
1,2
LINKS
EXAMPLE
For n=6: gcd(n!!+1,n-1) = 1 and gcd(n!!+2,n-2)=2, so that a(6)=2.
MATHEMATICA
b[n_]:=n!!; c[n_]:=n;
t=Table[m=1; While[GCD[b[n]+m, c[n]-m]==1, m++]; m, {n, 1, 200}] (* A214054 *)
Flatten[Position[t, 1]] (* A214585 *)
Flatten[Position[t, 2]] (* A214586 *)
CROSSREFS
Sequence in context: A339890 A351408 A205788 * A330739 A076398 A086257
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 21 2012
STATUS
approved