A249775 Least prime p such that the concatenation of primes from prime(n) to p is prime.

3, 0, 11, 19, 17, 79, 23, 151, 67, 53, 37, 107, 47, 131, 67, 71, 83, 0, 79, 137, 293, 131, 89, 101, 109, 113, 283, 149, 12923, 149, 317, 181, 1193, 157, 163, 157, 163, 193, 173, 18041, 307, 269, 227, 0, 2897, 211, 257, 331, 359, 239, 239, 251, 599, 257, 263, 269, 1531, 277, 313, 379, 1259

Offset

1,1

Comments

a(n) > 40000 or 0 for n = 2, 18, and 44.

Links

Table of n, a(n) for n=1..61.

Example

For n = 3, prime(3) = 5. 57 is not prime. 5711 is prime. Since 5711 = 5//7//11, a(3) = 11.

Prog

(PARI) a(n)=s=Str(prime(n)); forprime(p=prime(n)+1, 40000, s=concat(s, p); if(ispseudoprime(eval(s)), return(p))); 0
for(n=1, 50, print1(a(n), ", "))

Crossrefs

Cf. A249774.

Sequence in context: A216470 A182259 A211802 * A019264 A028851 A132221

Adjacent sequences: A249772 A249773 A249774 * A249776 A249777 A249778

Keyword

nonn,base

Author

Derek Orr, Nov 05 2014

Status

approved