A154530 Primes that are a concatenation of 2*k and 2*k+1 or 2*k and 2*k-1 for some k.

23, 43, 67, 89, 109, 1213, 2221, 2423, 3433, 3637, 4241, 4243, 5051, 5657, 5857, 6263, 6869, 7069, 7877, 7879, 8081, 8887, 9091, 9293, 9697, 10099, 102101, 102103, 108107, 108109, 112111, 114113, 120121, 124123, 126127, 138139, 148147, 150151

Offset: 1

Author

Pierre CAMI, Jan 11 2009

Keywords

• nonn
• base

Examples

			2*1=2, 2*1+1=3, and 23 the concatenation of 2 and 3 is prime, so a(1)=23
		

Links

• Pierre CAMI, Table of n, a(n) for n=1..10153

Crossrefs

Cf. A133986, A154531, A328903.

Cf. A010051, subsequence of A248378.

Programs

Haskell

a154530 n = a154530_list !! (n-1)
a154530_list = filter ((== 1) . a010051') a248378_list
-- Reinhard Zumkeller, Jun 27 2015

Extensions

Edited by Charles R Greathouse IV, Apr 28 2010