A064892 "Binary potency" of n-th prime p: length of shortest blocks of 0's inserted between the bits of p required to "dilute" it into a nonprime.

1, 2, 2, 1, 1, 1, 2, 1, 2, 3, 1, 1, 1, 3, 3, 3, 1, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 4, 2, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 2, 4, 2, 1, 2, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 4, 3, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 2, 1

Offset

1,2

Comments

Note that the +2 dilution of 3 is not the +1 dilution of 5!

Links

Table of n, a(n) for n=1..105.

Example

2nd prime = 3 = 11 -> 0101 = 5 -> 001001 = 9, so a(2) = 2; 3rd prime = 5 = 101 -> 010001 = 17 -> 001000001 = 65, so a(3) = 2

Crossrefs

A000040, A064891, A064893.

Sequence in context: A109072 A100727 A366134 * A236344 A333124 A274109

Adjacent sequences: A064889 A064890 A064891 * A064893 A064894 A064895

Keyword

base,easy,nonn

Author

Marc LeBrun, Oct 10 2001

Status

approved