A030458 Primes formed by concatenating n with n+1.

23, 67, 89, 1213, 3637, 4243, 5051, 5657, 6263, 6869, 7879, 8081, 9091, 9293, 9697, 102103, 108109, 120121, 126127, 138139, 150151, 156157, 180181, 186187, 188189, 192193, 200201, 216217, 242243, 246247, 252253, 270271, 276277, 278279, 300301, 308309, 312313, 318319

Offset

1,1

Comments

Primes in A030656.

Links

Paul Tek, Table of n, a(n) for n = 1..10000

Mathematica

Select[Table[FromDigits[Join[Flatten[IntegerDigits[{n, n+1}]]]], {n, 270}], PrimeQ] (* Jayanta Basu, May 16 2013 *)

Prog

(Magma) [m: n in [2..270 by 2] | IsPrime(m) where m is Seqint(Intseq(n+1) cat Intseq(n))];  // Bruno Berselli, Jun 18 2011
(PARI) forstep(n=2, 1e3, 2, if(isprime(k=eval(Str(n, n+1))), print1(k", "))) \\ Charles R Greathouse IV, Jun 18 2011
(Python)
from sympy import isprime
from itertools import count, islice
def agen(): yield from filter(isprime, (int(str(k)+str(k+1)) for k in count(2, 2)))
print(list(islice(agen(), 38))) # Michael S. Branicky, Aug 05 2022

Crossrefs

Cf. A052089, A052087, A052088.

Sequence in context: A059241 A241212 A052087 * A053559 A322414 A031376

Adjacent sequences: A030455 A030456 A030457 * A030459 A030460 A030461

Keyword

nonn,base

Author

Patrick De Geest

Status

approved