A098153 Summarize the previous term in binary (in increasing order).

1, 11, 101, 10101, 100111, 1001001, 1000111, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001, 1101001

Offset: 1

Author

Rick L. Shepherd, Aug 29 2004

Keywords

• base
• easy
• nonn

Comments

Similar to A005151 but uses base 2: Let a(1)=1. Describing a(1) as "one 1" again gives a(2)=11 (same digit string as A005151 and similar sequences), but describing a(2) as "two 1's" gives a(3)=101 when the frequency of digit occurrence is written in binary and followed by the digit counted.

Examples

			Summarizing a(8) = 1101001 in increasing digit order, there are "three 0's, four 1's", so concatenating 11 0 100 1 gives a(9) = 1101001 (=a(10)=a(11)=...).
		

Crossrefs

Cf. A098154 (ternary), A098155 (base 4), A005151 (decimal and digit strings for all other bases b >= 5).

Formula

a(n) = 1101001 for all n >= 8 (see example).