A114101 Begin with prime(1), then prime(2). After prime(j) write all the primes of the form prime(i) concatenated with prime(j) with i

2, 3, 23, 5, 7, 37, 11, 211, 311, 13, 313, 17, 317, 1117, 19, 719, 1319, 23, 223, 523, 1123, 1723, 29, 229, 1129, 31, 331, 1931, 37, 337, 3137, 41, 241, 541, 1741, 2341, 43, 743, 47, 347, 547, 1747, 2347, 53, 353, 1153, 1753, 2953, 4153, 59, 359

Offset: 1

Author

Amarnath Murthy, Nov 20 2005

Keywords

• base
• nonn

Examples

			11 is followed by 211, 311 (511 and 711 are not primes); then 13.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A114007.

Programs

Python

from itertools import islice
from sympy import isprime, nextprime
def agen(): # generator of terms
    p, s = 2, []
    while True:
        yield p; sp = str(p); s.append(sp); p = nextprime(p)
        yield from filter(isprime,  (int("".join(si + sp)) for si in s))
print(list(islice(agen(), 51))) # Michael S. Branicky, Jun 23 2023

Extensions

More terms from Amy Postell (arp179(AT)psu.edu), Feb 02 2006

Offset changed to 1 by Michael S. Branicky, Jun 23 2023