OFFSET
0,3
COMMENTS
Decimal conversions: 0, 1, 2, 6, 54, 3510, 14380470, 241264265751990, 67909853583655146508751957430, ... . (See A267348.) - Michael De Vlieger, Jan 06 2016
After 10, a(n) is '110' repeated 2^(n-3) times. Therefore, for n>3, a(n) is the concatenation of a(n-1) with itself.
After 1, each term with the 0's omitted is a member of A136308.
The number of digits in a(n) is A098011(n+1).
The number of digits in a(n+2)/a(n+1) gives A103204 with 2 repeated.
FORMULA
a(n) = 110*(10^(3*2^(n-3))-1)/999 for n>2. - Bruno Berselli, Jan 29 2016
EXAMPLE
a(3) = concat(1, 10, 110) = 110110.
a(4) = concat(1, 10, 110, 110110) = 110110110110.
MATHEMATICA
a = {0, 1}; Do[AppendTo[a, FromDigits@ Flatten@ Map[IntegerDigits@ # &, If[n < 2, Reverse@ a, a]]], {n, 8}]; a (* Michael De Vlieger, Jan 06 2016 *)
PROG
(Magma) [n le 2 select n*5^(n-1) else 110*(10^(3*2^(n-3))-1)/999: n in [0..8]]; // Bruno Berselli, Jan 29 2016
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Giovanni Teofilatto, Jan 06 2016
EXTENSIONS
Definition by Michael De Vlieger, Jan 06 2016
Edited by Editors of the OEIS, Jan 29 2016
STATUS
approved