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A103534
Concatenations of pairs of primes that differ by 1000.
3
131013, 191019, 311031, 611061, 971097, 1031103, 1091109, 1511151, 1631163, 1811181, 1931193, 2231223, 2291229, 2771277, 2831283, 3071307, 3671367, 3731373, 4091409, 4331433, 4391439, 4871487, 4991499, 5231523, 5711571
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