A081592 A self generating sequence: "there are n a(n)'s in the sequence". Start with 1,2 and use the rule : "a(n)=k implies there are n following k's (k is 1 or 2)".

1, 2, 1, 2, 2, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset: 1

Author

Benoit Cloitre, Apr 21 2003

Keywords

• nonn

Comments

Lengths of runs of consecutive 1's or 2's are : 1,1,2,3,9,21,117,588 ...

Examples

			Sequence begins : 1,2 . Since a(1)=1 there is only one following "1", gives 1,2,1. Since a(2)=2 there are 2 following "2's", gives 1,2,1,2,2. Since a(3)=1 there are 3 following "1's" 1,2,1,2,2,1,1,1 etc.