Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #10 Jan 21 2022 23:30:11
%S 3,1,3,111111111111111,33333,
%T 111111111111111111111111111111111111111111111111111111111111111111111111111111111111111,
%U 3333,111111111111111111111111111,33333
%N Copies of 3 and 1 alternately such that every partial concatenation is a prime.
%C The next term has 168 digits. - _Charles R Greathouse IV_, Sep 29 2008
%e 3, 31, 313, 313111111111111111, ... are all prime.
%Y Cf. A110774, A110775, A110776, A110777, A110778, A110779, A110780, A110781, A110782, A110783, A110788, A110789, A110791.
%K base,easy,nonn
%O 1,1
%A _Amarnath Murthy_, Aug 13 2005
%E a(6)-a(9) from_Charles R Greathouse IV_, Sep 29 2008