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 A154530 #10 Oct 31 2019 12:43:27 %S A154530 23,43,67,89,109,1213,2221,2423,3433,3637,4241,4243,5051,5657,5857, %T A154530 6263,6869,7069,7877,7879,8081,8887,9091,9293,9697,10099,102101, %U A154530 102103,108107,108109,112111,114113,120121,124123,126127,138139,148147,150151 %N A154530 Primes that are a concatenation of 2*k and 2*k+1 or 2*k and 2*k-1 for some k. %H A154530 Pierre CAMI, <a href="/A154530/b154530.txt">Table of n, a(n) for n=1..10153</a> %e A154530 2*1=2, 2*1+1=3, and 23 the concatenation of 2 and 3 is prime, so a(1)=23 %o A154530 (Haskell) %o A154530 a154530 n = a154530_list !! (n-1) %o A154530 a154530_list = filter ((== 1) . a010051') a248378_list %o A154530 -- _Reinhard Zumkeller_, Jun 27 2015 %Y A154530 Cf. A133986, A154531, A328903. %Y A154530 Cf. A010051, subsequence of A248378. %K A154530 nonn,base %O A154530 1,1 %A A154530 _Pierre CAMI_, Jan 11 2009 %E A154530 Edited by _Charles R Greathouse IV_, Apr 28 2010