A154963 Primes p such that the concatenation of p and prime(p) is prime.

2, 17, 23, 41, 61, 71, 83, 127, 227, 337, 353, 499, 503, 571, 727, 887, 911, 937, 971, 1061, 1427, 1579, 1663, 1693, 1709, 1871, 1877, 1907, 1949, 1973, 2017, 2063, 2081, 2239, 2339, 2393, 2467, 2713, 2797, 2939, 2999, 3181, 3271, 3463, 3643, 3659, 3677

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

Concatenation of prime 2 and second prime 3 is the prime 23, hence 2 is in the sequence.
Concatenation of prime 23 and 23rd prime 83 is the prime 2383, hence 23 is in the sequence.

Mathematica

A154963 = Select[ Prime[ Range[ 550 ] ], PrimeQ[ FromDigits[ Join[ IntegerDigits[ # ], IntegerDigits[ Prime[ # ] ] ] ] ] & ] (* Alonso del Arte Nov 12 2009 *)

Prog

(Magma) [ p: p in PrimesUpTo(3700) | IsPrime(StringToInteger(IntegerToString(p) cat IntegerToString(NthPrime(p)))) ];

Crossrefs

Cf. A045532, A155032 (resulting primes).

Sequence in context: A094668 A019421 A105901 * A343241 A049562 A107137

Adjacent sequences: A154960 A154961 A154962 * A154964 A154965 A154966

Keyword

nonn,base,easy,less

Author

Juri-Stepan Gerasimov, Jan 18 2009

Extensions

Edited and extended beyond a(3) by Klaus Brockhaus, Jan 20 2009

Status

approved