A061519 a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 5.

1, 6, 11, 66, 1111, 6666, 11111111, 66666666, 1111111111111111, 6666666666666666, 11111111111111111111111111111111, 66666666666666666666666666666666

Offset: 0

Author

Amarnath Murthy, May 08 2001

Keywords

• base
• nonn

Comments

In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.

Number of digits of each term is the sequence A016116. [From Dmitry Kamenetsky, Jan 17 2009]

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..13

Programs

Mathematica

With[{nn=5},Join[Table[FromDigits[PadRight[{},2^n,1]],{n,0,nn}],Table[FromDigits[PadRight[{},2^n,6]],{n,0,nn}]]]//Sort (* Harvey P. Dale, Jan 23 2025 *)

Formula

a(2n) = 6*[10^{2^(n)} - 1]/9 a(2n+1) = [10^(2^n) - 1]/9

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001