A283481 Positions of odd terms in A004001.

1, 2, 5, 9, 11, 12, 17, 19, 22, 25, 26, 27, 33, 35, 37, 38, 40, 43, 46, 47, 48, 50, 51, 55, 56, 57, 58, 65, 67, 69, 72, 74, 77, 79, 80, 82, 83, 87, 89, 90, 92, 93, 97, 100, 101, 102, 107, 110, 111, 112, 117, 118, 119, 120, 121, 129, 131, 133, 135, 136, 138, 140, 143, 145, 148, 150, 151, 153, 154, 158, 160, 163, 165, 166, 168, 169

Offset: 1

Author

Antti Karttunen, Mar 18 2017

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..8121

Crossrefs

Cf. A283482 (complement), A283480 (a left inverse).

Positions of ones in A095901.

Cf. A004001.

Programs

Mathematica

a[n_] := a[n] = If[n <= 2, 1, a[a[n - 1]] + a[n - a[n - 1]]]; Select[Range@ 169, OddQ@ a[#] &] (* Michael De Vlieger, Mar 18 2017, after Robert G. Wilson v at A004001 *)

Formula

Other identities. For all n >= 1:

A283480(a(n)) = n.