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A350401
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Primes p such that if q is the next prime, p*q mod (A004086(p)+A004086(q)) is prime.
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1
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3, 5, 7, 11, 13, 23, 29, 31, 53, 59, 71, 73, 83, 89, 101, 107, 109, 127, 137, 149, 163, 173, 181, 191, 193, 211, 223, 227, 233, 239, 257, 271, 277, 281, 283, 307, 317, 367, 373, 389, 409, 419, 431, 449, 461, 463, 467, 479, 491, 509, 521, 523, 547, 577, 587, 593, 607, 613, 631, 641, 643, 653, 659
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(6) = 23 is a member because it is prime, the next prime is 29, and 23*29 mod (32+92) = 667 mod 124 = 47 is prime.
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MAPLE
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revdigs:= proc(n) local L, i, m;
L:= convert(n, base, 10); m:= nops(L);
add(L[i]*10^(m-i), i=1..m)
end proc:
q:= 2: qr:= 2:
R:= NULL: count:= 0:
while count < 100 do
p:=q; pr:= qr;
q:= nextprime(p); qr:= revdigs(q); s:= p*q mod (pr+qr);
if isprime(s) then
R:= R, p; count:= count+1;
fi
od:
R;
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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