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!)
 A056212 Primes p whose period of reciprocal equals (p-1)/7. 12
 211, 617, 1499, 2087, 2857, 6007, 6469, 7127, 7211, 7589, 9661, 10193, 13259, 13553, 14771, 18047, 18257, 19937, 20903, 21379, 23549, 26153, 27259, 27539, 32299, 33181, 33461, 34847, 35491, 35897, 41651, 42407, 42491, 43051, 43793 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Cyclic numbers of the seventh degree (or seventh order): the reciprocals of these numbers belong to one of seven different cycles. Each cycle has the (number minus 1)/7 digits. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 MATHEMATICA f[n_Integer] := Block[{ds = Divisors[n - 1]}, (n - 1)/Take[ ds, Position[ PowerMod[ 10, ds, n], 1] [[1, 1]]] [[ -1]]]; Select[ Prime[ Range[4, 4700]], f[ # ] == 7 &] CROSSREFS Cf. A097443, A055628, A056157, A056210, A056211, A056213, A056214, A056215, A056216, A056217, A098680, A135073. Sequence in context: A300334 A032659 A098674 * A299110 A236722 A236878 Adjacent sequences:  A056209 A056210 A056211 * A056213 A056214 A056215 KEYWORD nonn,base AUTHOR Robert G. Wilson v, Aug 02 2000 EXTENSIONS Edited by N. J. A. Sloane, Apr 30 2007 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 July 31 22:21 EDT 2021. Contains 346377 sequences. (Running on oeis4.)