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

1,2

Comments

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

Links

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

Example

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.

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@# &]

Crossrefs

Cf. A208884.

Sequence in context: A358433 A344540 A338785 * A093079 A377841 A095417

Adjacent sequences: A335814 A335815 A335816 * A335818 A335819 A335820

Keyword

nonn

Author

Giovanni Resta, Jun 25 2020

Status

approved