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%I #8 Apr 03 2023 10:36:10
%S 2,2,2,2,2,2,3,2,3,2,2,2,2,2,2,3,2,3,2,3,3,3,3,3,3,2,2,3,2,2,3,2,2,3,
%T 2,3,3,2,2,2,3,2,3,3,3,3,2,3,2,4,3,2,2,3,2,2,2,2,3,3,2,2,3,2,2,3,2,3,
%U 3,2,2,2,3,2,2,3,2,2,3,2,3,3,2,3,4,2,2,3,3,3,3,3,2,2,3,2,2,3,3,2,2,3,2,3,2
%N Number of distinct prime factors of concatenated twin primes.
%H Chris Caldwell, <a href="https://t5k.org/lists/small/1ktwins.txt">The First 1,008 Twin Primes</a>.
%e The number of distinct prime factors of 35 (which is obtained from concatenating the twin primes 3 and 5) is 2, which is the first term of the sequence.
%t Length[ FactorInteger[ # ]] & /@ FromDigits /@ Transpose[{Select[ Prime[ Range[550]], PrimeQ[ # + 2] &], Select[ Prime[ Range[550]], PrimeQ[ # - 2] &]}] (* _Robert G. Wilson v_, Jun 09 2005 *)
%Y Cf. A001359, A006512, A077800.
%K nonn,base
%O 1,1
%A _Parthasarathy Nambi_, Jun 04 2005
%E Edited, corrected and extended by _Robert G. Wilson v_, Jun 09 2005
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