A175336 a(1)=1. For n>1, a(n) equals the smallest number > a(n-1) of the form a(k) U j U a(k) U j, where U represents concatenation (written in decimal) of the binary representation of the arguments, where 1<=k < n, and j = {0} or {1} or {}.

1, 3, 10, 15, 54, 63, 170, 255, 660, 693, 990, 1023, 3510, 4095, 13932, 14061, 16254, 16383, 43690, 65535, 174420, 174933, 261630, 262143, 676500, 710325, 1014750, 1048575, 2704680, 2706729, 2839914, 2841963, 4057020, 4059069, 4192254, 4194303

Offset

1,2

Comments

Each term of sequence A175335 exists in this sequence.

Links

Table of n, a(n) for n=1..36.

Example

10 (decimal), a term of the sequence, written in binary is 1010. Letting j={0}, we have that the decimal value of 1010 U 0 U 1010 U 0 = 1010010100, which is 660, is in the sequence.
Letting j = the empty string instead, and keeping a(k) = 10, we have the concatenation 1010 U 1010, which is 10101010. This is 170 in decimal, so 170 is in this sequence.

Crossrefs

Cf. A175335

Sequence in context: A023861 A037345 A217278 * A370437 A259877 A182334

Adjacent sequences: A175333 A175334 A175335 * A175337 A175338 A175339

Keyword

base,nonn

Author

Leroy Quet, Apr 14 2010

Extensions

Missing term 255 and many more terms added by Max Alekseyev, Jun 13 2011

Status

approved