A280376 Primes formed from the concatenation of n and nextprime(n).

23, 67, 811, 911, 1213, 2729, 3137, 3637, 4243, 4447, 4547, 5153, 5659, 6367, 6871, 6971, 7879, 8389, 8689, 9397, 9497, 9697, 98101, 102103, 104107, 105107, 108109, 115127, 117127, 118127, 123127, 126127, 132137, 138139, 150151, 151157, 154157, 156157, 157163

Offset: 1

Author

K. D. Bajpai, Jan 01 2017

Keywords

• nonn
• base

Examples

			811 is in the sequence because it is prime formed from the concatenation of 8 and 11, where 11 is the prime next to 8.
3137 is in the sequence because it is prime formed from the concatenation of 31 and 37, where 37 is the prime next to 31.
		

Links

• K. D. Bajpai, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A084667, A084669, A151800.

Subsequence of primes of A049852.

Programs

Magma

[p : n in[1 .. 200] | IsPrime (p) where p is Seqint(Intseq (NextPrime(n)) cat Intseq(n))];

Maple

f:= proc(n) local x,p;
   p:= nextprime(n);
   x:= n*10^(1+ilog10(p))+p;
   if isprime(x) then x else NULL fi
end proc:
map(f, [$1..200]); # Robert Israel, Jan 01 2017

Mathematica

Select[Table[FromDigits[Join[IntegerDigits[n], IntegerDigits[NextPrime[n]]]], {n,500}], PrimeQ]