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Primes formed by concatenating n consecutive increasing numbers starting with a palindrome and ending with the next consecutive palindrome.
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%I #10 Sep 14 2018 04:59:44

%S 23,67,89,131132133134135136137138139140141

%N Primes formed by concatenating n consecutive increasing numbers starting with a palindrome and ending with the next consecutive palindrome.

%C The next term, a(5) = 90809...90909, has 505 digits. - _M. F. Hasler_, Sep 11 2018

%o (PARI) P=1; until(, N=P; for(x=1+P, P=A262038(1+P), N=N*10^(logint(x, 10)+1)+x); ispseudoprime(N)&& print(N",")) \\ _M. F. Hasler_, Sep 11 2018

%Y Cf. A000040, A002113.

%K base,nonn

%O 1,1

%A _G. L. Honaker, Jr._, Jan 16 2000