A105840 Primes of the form r(r(n)+1)+1, where r(n) = A141468(n) = n-th nonprime.

2, 11, 17, 23, 31, 37, 41, 47, 59, 67, 71, 73, 79, 83, 89, 97, 101, 103, 109, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 191, 197, 199, 211, 223, 227, 233, 239, 241, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 331, 347, 349, 353, 359, 367

Offset: 1

Author

Juri-Stepan Gerasimov, Aug 25 2008

Keywords

• nonn

Examples

			If n=1, then r(r(1)+1)+1=r(0+1)+1=r(1)+1=0+1=1 (nonprime).
If n=2, then r(r(2)+1)+1=r(1+1)+1=r(2)+1=1+1=2=a(1).
If n=3, then r(r(3)+1)+1=r(4+1)+1=r(5)+1=8+1=9 (nonprime).
If n=4, then r(r(4)+1)+1=r(6+1)+1=r(7)+1=10+1=11=a(2).
If n=5, then r(r(5)+1)+1=r(8+1)+1=r(9)+1=14+1=15 (nonprime).
If n=6, then r(r(6)+1)+1=r(9+1)+1=r(10)+1=15+1=16 (nonprime).
If n=7, then r(r(7)+1)+1=r(10+1)+1=r(11)+1=16+1=17=a(3).
If n=8, then r(r(8)+1)+1=r(12+1)+1=r(13)+1=20+1+21 (nonprime).
If n=9, then r(r(9)+1)+1=r(14+1)+1=r(15)+1=22+1=23=a(4), etc.
		

Crossrefs

Cf. A000040, A141468.

Extensions

53 removed, more terms added by R. J. Mathar, Sep 05 2008