OFFSET
1,1
COMMENTS
All terms are multiples of 3.
FORMULA
a(n) = Concatenate(P, P+1000) iff P prime and P+1000 prime.
EXAMPLE
1811181 is in this sequence because 181 is prime, 181+1000 = 1181 is prime and those two primes are concatenated.
MATHEMATICA
10001#+1000&/@Select[Prime[Range[150]], PrimeQ[#+1000]&] (* Harvey P. Dale, Sep 01 2017 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, Mar 22 2005
STATUS
approved