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Smallest prime of the form: all twos followed by prime(n). a(n) > prime(n). 0 if no such prime exists.
4

%I #16 Jul 06 2019 14:20:33

%S 0,23,0,227,211,2213,

%T 22222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222217,

%U 2222219,223,229,2222222222222222222222222231,2237,241,2243,22247

%N Smallest prime of the form: all twos followed by prime(n). a(n) > prime(n). 0 if no such prime exists.

%C Prime(n) is all zeros followed by prime(n). This is all twos followed by prime(n). Conjecture: No term is zero except a(1) = a(3) = 0.

%C a(6) has not been proved prime, but it is a probable prime. - _Joshua Zucker_, May 06 2006

%C The 206-digit number 222...217 is, in fact, prime, as quickly confirmed by the Magma Calculator (http://magma.maths.usyd.edu.au/calc/). - _Jon E. Schoenfield_, Aug 24 2009

%e a(6) = 2213, as 213 is composite prime(6) = 13.

%Y Cf. A114783.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Nov 17 2005

%E More terms from _Joshua Zucker_, May 06 2006

%E Edited by _T. D. Noe_, Oct 30 2008