A173269 2*prime(prime(n))-3 and 3*prime(prime(n))-2 are both primes.

1, 2, 3, 8, 11, 14, 15, 19, 23, 24, 28, 39, 44, 47, 54, 62, 63, 81, 85, 101, 121, 122, 124, 136, 152, 159, 180, 218, 219, 241, 247, 253, 274, 290, 298, 307, 323, 324, 341, 361, 371, 376, 381, 403, 410, 413, 441, 443, 479, 487, 499, 552, 554, 556, 562, 582, 622

Offset: 1

Author

Juri-Stepan Gerasimov, Feb 14 2010

Keywords

• nonn

Examples

			a(1)=1 because 2*p(p(1))-3=2*p(2)-3=2*3-3=3=prime and 3*p(p(1))-2=7=prime; a(2)=2 because 2*p(p(2))-3=2*p(3)-3=2*5-3=7=prime and 3*p(p(2))-2=13=prime; a(3)=3 because 2*p(p(3))-3=2*p(5)-3=2*11-3=19=prime and 3*p(p(3))-2=31=prime; a(4)=8 because 2*p(p(8))-3=2*p(19)-3=2*67-3=131=prime and 3*p(p(8))-2=199=prime.
		

Crossrefs

Cf. A063908, A088878.

Extensions

Inserted 23 and 24, removed 34, extended the sequence - R. J. Mathar, Mar 01 2010