OFFSET
1,1
COMMENTS
Except a(1), all the terms in this sequence are congruent to 1 mod 3.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
823 is in the sequence because it is a prime obtained by prefixing an 8 to the prime 23.
8317 is in the sequence because it is a prime obtained by prefixing an 8 to the prime 317.
MATHEMATICA
Select[k = 8; Table[FromDigits[Join[IntegerDigits[k], IntegerDigits[Prime[n]]]], {n, 500}], PrimeQ]
PROG
(PARI) forprime(p = 2, 5000, k=eval(concat(8, Str(p))); if(isprime(k), print1(k, ", ")));
(Magma) [k : p in PrimesUpTo (5000) | IsPrime (k) where k is Seqint (Intseq (p) cat Intseq (8))];
CROSSREFS
KEYWORD
nonn,base
AUTHOR
K. D. Bajpai, Jul 30 2017
STATUS
approved