A335817 a(k) is the index of the first occurrence of 2*k-1 in A208884, or 0 if it does not occur.

1, 2, 13, 4, 6, 75, 22975, 11, 15, 10, 1417, 37, 17, 12, 573, 19, 16, 49, 28, 227, 34, 18, 26, 31, 1371, 20, 41, 36, 8181, 339, 38, 30, 40, 207, 43, 70, 1113, 91, 235, 32, 63, 203, 50, 60, 103, 48, 189, 42, 421, 57, 74, 98, 65, 259, 11997, 155, 44, 54, 199, 67

Offset: 1

Author

Giovanni Resta, Jun 25 2020

Keywords

• nonn

Comments

It is conjectured that A208884 contains all the odd numbers. If so, a(n) > 0 for every n.

Examples

			The first terms of A208884 are 1, 3, 3, 7, 3, so a(2*1-1) = 1, a(2*2-1) = 2, and a(2*4-1) = 4.
		

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A208884.

Programs

Mathematica

b[1]=1; b[n_] := b[n] = #/2^IntegerExponent[#, 2] &@ (n + b[n-1]); A = Transpose@ {b /@ #, #} &@ Range[25000]; A = DeleteDuplicatesBy[ Sort@ A, First]; Last /@ TakeWhile[ A, A[[ (First[#] + 1)/2, 1]] == First@# &]