This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A124977 Least positive number k such that 2^k mod k = 2n+1, or 0 if no such k exists. 8
 0, 4700063497, 19147, 25, 2228071, 262279, 95, 481, 45, 2873, 3175999, 555, 95921, 174934013, 777, 140039, 2463240427, 477, 91, 623, 2453, 55, 345119, 1131, 943, 21967, 135, 46979, 125, 3811, 23329, 155, 1064959, 245 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA A bisection of A036236: a(n) = A036236(2n+1). EXAMPLE a(3) = 25 because 2^25 = 33554432 = 7 + 25*1342177. MATHEMATICA nk[n_] := Module[ {k}, k = 1;   While[PowerMod[2, k, k] != 2 n + 1, k++]; k] Join[{0}, Table[nk[i], {i, 1, 33}]]  (* Robert Price, Oct 11 2018 *) CROSSREFS Cf. A122182, A050259, A033981, A124974, A124965, A015910, A015911. Cf. A015910, A015911, A033981, A050259, A124965, A124974. Sequence in context: A172726 A172797 A199631 * A128172 A050259 A249972 Adjacent sequences:  A124974 A124975 A124976 * A124978 A124979 A124980 KEYWORD nonn AUTHOR Zak Seidov, Nov 14 2006 EXTENSIONS Edited by Max Alekseyev, May 20 2011 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 June 17 22:17 EDT 2019. Contains 324200 sequences. (Running on oeis4.)