A134365 In base 2 the least number of positive numbers of (1+n) digits in which it can be read the totality of the 2^(n-1) positive numbers of n digits (0 excluded).

1, 1, 3, 5, 10, 20, 44

Offset

1,3

Links

Table of n, a(n) for n=1..7.

Example

The unique number 1 of 1 digit can be read in 1 number of 2 digits = 10, hence c(n) = 1.
The 2 numbers of 2 digits 10 and 11 can be read in 1 number of 3 digits = 110, hence c(2)=1.
The four numbers of 3 digits 100,101,110,111 need 3 digits of 4 digits : e.g 1000 (100)1010(101)1110 (110 and 111); 2 numbers are not enough because 1010 for example contains only one number of 3 digits and for the second reason that 1100 and 1101 contain each the number 110.

Crossrefs

Sequence in context: A270737 A270724 A018104 * A076862 A107129 A037183

Adjacent sequences: A134362 A134363 A134364 * A134366 A134367 A134368

Keyword

base,easy,nonn

Author

Philippe Lallouet (philip.lallouet(AT)orange.fr), Jan 17 2008

Status

approved