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A280376
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Primes formed from the concatenation of n and nextprime(n).
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1
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23, 67, 811, 911, 1213, 2729, 3137, 3637, 4243, 4447, 4547, 5153, 5659, 6367, 6871, 6971, 7879, 8389, 8689, 9397, 9497, 9697, 98101, 102103, 104107, 105107, 108109, 115127, 117127, 118127, 123127, 126127, 132137, 138139, 150151, 151157, 154157, 156157, 157163
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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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811 is in the sequence because it is prime formed from the concatenation of 8 and 11, where 11 is the prime next to 8.
3137 is in the sequence because it is prime formed from the concatenation of 31 and 37, where 37 is the prime next to 31.
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MAPLE
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f:= proc(n) local x, p;
p:= nextprime(n);
x:= n*10^(1+ilog10(p))+p;
if isprime(x) then x else NULL fi
end proc:
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MATHEMATICA
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Select[Table[FromDigits[Join[IntegerDigits[n], IntegerDigits[NextPrime[n]]]], {n, 500}], PrimeQ]
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PROG
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(Magma) [p : n in[1 .. 200] | IsPrime (p) where p is Seqint(Intseq (NextPrime(n)) cat Intseq(n))];
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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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