A120241 a(n) = (n - 2^floor(log(n)/log(2)) + 1)-th integer among those positive integers not among the earlier terms of the sequence.

1, 2, 4, 3, 6, 8, 10, 5, 9, 12, 14, 16, 18, 20, 22, 7, 13, 17, 21, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 11, 19, 25, 29, 33, 37, 41, 45, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 15, 27, 35, 43, 49, 53, 57, 61, 65

Offset

1,2

Comments

This sequence is a permutation of the positive integers. n - 2^floor(log(n)/log(2)) + 1 = A062050(n).

Links

Ivan Neretin, Table of n, a(n) for n = 1..8191

Example

The first 6 terms of the sequence are 1,2,4,3,6,8. Now 7 - 2^floor(log(7)/log(2)) + 1 = 4. So we want the 4th term of those positive integers not occurring among the first 6 terms of the sequence (i.e., the 4th term among 5,7,9,10,11,...). So a(7) = 10.

Mathematica

Fold[Append[#1, Complement[Range[Max[#1] + #2], #1][[#2]]] &, {1},
Flatten@Table[Range[2^k], {k, 6}]] (* Ivan Neretin, Sep 24 2021 *)

Crossrefs

Cf. A120242, A062050.

Sequence in context: A039864 A101906 A297403 * A352714 A355435 A155487

Adjacent sequences: A120238 A120239 A120240 * A120242 A120243 A120244

Keyword

easy,nonn

Author

Leroy Quet, Jun 11 2006

Extensions

Extended by Ray Chandler, Jun 19 2006

Status

approved