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%I #4 Dec 06 2015 23:13:31
%S 2,3,5,11,13,23,31,37,41,43,53,101,103,113,131,137,151,211,223,233,
%T 241,251,307,311,313,331,337,401,421,431,433,443,503,1009
%N a(n) = smallest prime > a(n-1) such that in the sum a(n-1) + a(n) there are no carries, with a(1)=2.
%C For each digit place we must have sum of digits of a(n) and a(n-1) less than 10.
%C The sequence terminates if a(n) is a prime of form 10k+9 (A030433).
%C It seems very likely that the sequence is finite for any a(1).
%C E.g., sequence with a(1)=1013 terminates at a(8060)=10000019.
%e After 5 we cannot use 7 because 5 + 7 = 12 and here 1 carries to the next digit place.
%K fini,full,nonn,base
%O 1,1
%A _Zak Seidov_, Jul 11 2010