The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Clark Kimberling, Table of n, a(n) for n = 1..1000 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 Cf. A214585, A214586. Sequence in context: A318749 A050330 A205788 * A330739 A076398 A086257 Adjacent sequences:  A214051 A214052 A214053 * A214055 A214056 A214057 KEYWORD nonn,easy AUTHOR Clark Kimberling, Jul 21 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 1 08:39 EDT 2020. Contains 337442 sequences. (Running on oeis4.)