A080154 Values of n corresponding to the terms in sequence A080153.

1, 2, 5, 9, 11, 13, 17, 22, 25, 28, 30, 36, 38, 41, 45, 48, 49, 53, 55, 58, 68, 76, 84, 85, 91, 94, 101, 114, 137, 139, 147, 153, 154, 156, 163, 165, 180, 189, 195, 200, 210, 211, 223, 235, 237, 241, 246, 247, 249, 253, 256, 272, 274, 286, 289, 293, 296, 306, 321, 323

Offset: 1

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 31 2003

Keywords

• nonn
• base

Examples

			E.g. the first three terms are 1, 2 and 5 because the concatenation of the first, 2nd and 11th primes is 2311 and this is prime. Also, the 5th prime is the first one after 3 for which this concatenation is prime.
		

Crossrefs

Cf. A073640, A080153.

Programs

Maple

with(numtheory): pout := [2,3]: nout := [1,2]: for n from 3 to 600 do: p := ithprime(n): d := parse(cat(pout[nops(pout)-1],pout[nops(pout)],p)): if (isprime(d)) then pout := [op(pout),p]: nout := [op(nout),n]: fi: od: nout;

Formula

For each term a(n) in this sequence, A080153(n) = prime(a(n)).

Extensions

Edited by Charles R Greathouse IV, Apr 30 2010