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%I #9 Oct 10 2012 15:34:52
%S 13,61,73,181,37,97,109,193,229,157,241,313,349,277,337,397,421,373,
%T 541,433,409,457,757,661,577,709,613,601,853,769,733,1021,997,877,829,
%U 673,1033,1009,1069,1117,1129,937,1201,1297,1549,1093,1153,1249,1213,1381
%N a(n) is the least unused prime greater than 3 such that (a(n) + a(n-1))/2 is prime, with a(0)=13.
%C Conjecture: every prime of the form 12k+1 is a member.
%p a:=5:
%p l:=13:
%p L:=[l]:
%p while l < 3400 do
%p if isprime((l+a)/2) then
%p if not(a in L) then
%p if not a mod 12 = 1 then
%p print(a);
%p break;
%p end if;
%p L:=[op(L),a]:
%p l:=a:
%p a:=5:
%p else
%p a:=nextprime(a):
%p end if;
%p else
%p a:=nextprime(a):
%p end if;
%p end do;
%p L;
%Y Cf. A086519.
%K nonn
%O 0,1
%A _Pedja Terzic_, Oct 08 2012
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