A195610 Smallest k such that A014657(n) divides 2^k + 1.

0, 0, 1, 2, 3, 5, 6, 4, 9, 10, 9, 14, 5, 18, 10, 7, 26, 9, 29, 30, 6, 33, 27, 41, 24, 15, 50, 53, 18, 14, 55, 50, 7, 65, 34, 69, 14, 74, 26, 81, 78, 9, 86, 29, 89, 90, 18, 48, 98, 33, 10, 45, 105, 113, 38, 12, 81, 41, 25, 8, 26, 134, 46, 35, 47, 68, 146, 45

Offset: 1

Author

Reinhard Zumkeller, Sep 21 2011

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000051, A014657, A195470, A337220.

Programs

Haskell

import Data.List (elemIndex)
import Data.Maybe (catMaybes)
a195610 n = a195610_list !! (n-1)
a195610_list = catMaybes $ map k [1..] where
   k x = elemIndex 0 $ map (`mod` x) $ take (fromInteger x) a000051_list

Formula

2^a(n) + 1 = A337220(n)*A014657(n), n>=1. - Wolfdieter Lang, Aug 22 2020