A185038 Positions at which A090895 (a(1) = 1 then a(n) = a(n-1)/2 if a(n-1) is even, a(n) = a(n-1) + n otherwise) reach the value of 1.

1, 8, 15, 64, 7069, 229826, 62906548, 104509874538, 209233407362, 474536678820, 2653613575299, 14802269029898

Offset: 1

Author

Sergio Pimentel, Mar 01 2012

Keywords

• more
• hard
• nonn

Comments

It seems that this sequence is infinite.

Examples

			Example: the sequence a(1)=1 then a(n)=a(n-1)/2 if a(n-1) is even, a(n) = a(n-1) + n otherwise goes 1, 3, 6, 3, 8, 4, 2, 1, 10, 5, 16, 8, 4, 2, 1, etc... which has ones at 1, 8, 15, 64, etc...
		

Crossrefs

Cf. A090895.

Programs

Haskell

import Data.List (elemIndices)
a185038 n = a185038_list !! (n-1)
a185038_list = map (+ 1) $ elemIndices 1 a090895_list
-- Reinhard Zumkeller, Mar 02 2012

Extensions

a(8)-a(12) from Hiroaki Yamanouchi, Oct 04 2014