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A329737
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Cyclops primes that remain prime after being "blinded".
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2
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101, 103, 107, 109, 307, 401, 503, 509, 601, 607, 701, 709, 809, 907, 11071, 11087, 11093, 12037, 12049, 12097, 13099, 14029, 14033, 14051, 14071, 14081, 14083, 14087, 15031, 15053, 15083, 16057, 16063, 16067, 16069, 16097, 17021, 17033, 17041, 17047, 17053
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OFFSET
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1,1
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COMMENTS
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There are 14 of these primes with 3 digits and 302 with 5 digits.
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LINKS
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EXAMPLE
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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.
307 is a term because when you remove the "0" it remains a prime: 37.
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PROG
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(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
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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