A084667 Primes which are a concatenation of n and prime(n).

23, 47, 613, 1237, 1759, 1861, 2383, 27103, 30113, 35149, 36151, 41179, 42181, 45197, 46199, 54251, 56263, 57269, 58271, 61283, 71353, 82421, 83431, 85439, 92479, 93487, 99523, 115631, 117643, 119653, 121661, 123677, 127709, 136769, 141811, 145829, 147853

Offset

1,1

Comments

Is the sequence infinite? - Zak Seidov, Nov 19 2013

Links

Zak Seidov, Table of n, a(n) for n = 1..20000

Example

a(3) = 613 because prime(6) = 13 and 613 is prime,
a(1000) = 761077477 because prime(7610) = 77477 and 761077477 is prime.
a(20000) = 2092142886529 because prime(209214) = 2886529 and 2092142886529 is prime.

Mathematica

Select[Table[FromDigits[Flatten[{IntegerDigits[n], IntegerDigits[Prime[n]]}]], {n, 1, 500}], PrimeQ] (* Alonso del Arte, Sep 22 2004 *)

Prog

(Magma) [p: n in [1..200] | IsPrime(p) where p is Seqint(Intseq(NthPrime(n)) cat Intseq(n))]; // Bruno Berselli, Sep 15 2015
(PARI) lista(NN) = for(k=1, NN, p=prime(k); if(isprime(j=k*10^#digits(p)+p), print1(j, ", "))) \\ Jinyuan Wang, Apr 05 2019

Crossrefs

Cf. A084669.

Sequence in context: A247673 A216569 A042054 * A255596 A157358 A158238

Adjacent sequences: A084664 A084665 A084666 * A084668 A084669 A084670

Keyword

nonn,base

Author

Zak Seidov, Jun 29 2003

Status

approved