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