This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A103534 #14 Mar 01 2023 05:42:50 %S A103534 131013,191019,311031,611061,971097,1031103,1091109,1511151,1631163, %T A103534 1811181,1931193,2231223,2291229,2771277,2831283,3071307,3671367, %U A103534 3731373,4091409,4331433,4391439,4871487,4991499,5231523,5711571 %N A103534 Concatenations of pairs of primes that differ by 1000. %C A103534 All terms are multiples of 3. %F A103534 a(n) = Concatenate(P, P+1000) iff P prime and P+1000 prime. %e A103534 1811181 is in this sequence because 181 is prime, 181+1000 = 1181 is prime and those two primes are concatenated. %t A103534 10001#+1000&/@Select[Prime[Range[150]],PrimeQ[#+1000]&] (* _Harvey P. Dale_, Sep 01 2017 *) %Y A103534 Cf. A100750, A103195, A103206, A104718, A104719, A103523. %K A103534 base,easy,nonn %O A103534 1,1 %A A103534 _Jonathan Vos Post_, Mar 22 2005