OFFSET
1,2
COMMENTS
By "run" of 0's or 1's, it is meant: Think of binary k as a string of 0's and 1's. A single run of the digit b (0 or 1) is made up completely of consecutive digits all equal to b, and is bounded on its ends by either the digit 1-b or by the end of the string.
EXAMPLE
For n = 4, we check: 4 in binary is 100, which has a run of two 0's; and 2 is not coprime to 4. But 2*4 = 8 = 1000 in binary has a run of one 1 and a run of three 0's. Since both 1 and 3 are coprime to 4, a(4) = 8.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Leroy Quet, Jul 05 2009
EXTENSIONS
More terms from Sean A. Irvine, Jan 27 2011
STATUS
approved