A118144 Numbers of prime factors of l, where l is defined in A118534.

0, 0, 1, 0, 2, 2, 2, 2, 1, 3, 2, 2, 2, 2, 1, 1, 2, 2, 3, 2, 1, 3, 2, 4, 2, 3, 3, 3, 3, 3, 2, 3, 4, 2, 3, 2, 1, 2, 2, 1, 2, 3, 4, 4, 3, 2, 1, 2, 4, 4, 1, 2

Offset: 1

Author

Rémi Eismann and Fabien Sibenaler, May 14 2006, Feb 14 2008

Keywords

• nonn

Comments

a(n) = 0 only for n = 1, 2 and 4.

Examples

			For a(1), l=0 thus a(1)=0,
for a(3), l=3 thus a(3)=1,
for a(8), l=15=3*5 thus a(8)=2,
for a(24), l=81=3*3*3*3 thus a(24)=4.
		

Links

• Remi Eismann, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A118534, A117563, A118123, A117078.

Formula

a(n) = numbers of factors of l, largest l such that prime(n+1) = prime(n) + (prime(n) mod l), or 0 if no such l exists.