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 #58 Sep 08 2022 08:46:24
%S 101,103,107,109,307,401,503,509,601,607,701,709,809,907,11071,11087,
%T 11093,12037,12049,12097,13099,14029,14033,14051,14071,14081,14083,
%U 14087,15031,15053,15083,16057,16063,16067,16069,16097,17021,17033,17041,17047,17053
%N Cyclops primes that remain prime after being "blinded".
%C There are 14 of these primes with 3 digits and 302 with 5 digits.
%H Rodolfo Ruiz-Huidobro, <a href="/A329737/b329737.txt">Table of n, a(n) for n = 1..3194</a>
%e The first term, a(1), is 101 because if you remove the "cyclops' eye" it remains a prime (11) and because 101 is the 1st cyclops prime.
%e 307 is a term because when you remove the "0" it remains a prime: 37.
%o (Magma) a:=[]; f:=func<n|IsPrime(n) and IsOdd(#a) and a[(#a+1) div 2] eq 0 and not 0 in a[1..(#a-1) div 2] cat a[(#a+3) div 2..#a] where a is Intseq(n)>; g:=func<n|Seqint(a[1..(#a-1) div 2] cat a[(#a+3) div 2..#a]) where a is Intseq(n)>; for n in [1..20000] do if f(n) and IsPrime(g(n)) then Append(~a,n); end if; end for; a; // _Marius A. Burtea_, Nov 20 2019
%Y Intersection of A256186 and A134809.
%K nonn,base,easy
%O 1,1
%A _Rodolfo Ruiz-Huidobro_, Nov 20 2019