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A289866
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Primes obtained from other primes by prefixing a 1.
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4
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13, 17, 113, 131, 137, 167, 173, 179, 197, 1103, 1109, 1151, 1163, 1181, 1193, 1223, 1229, 1277, 1283, 1307, 1367, 1373, 1409, 1433, 1439, 1487, 1499, 1523, 1571, 1601, 1607, 1613, 1619, 1709, 1733, 1787, 1811, 1823, 1877, 1907, 1997, 11069, 11087, 11093
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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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131 is in the sequence because is a prime obtained by prefixing a 1 to the prime 31.
1409 is in the sequence because is a prime obtained by prefixing a 1 to the prime 409.
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MATHEMATICA
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Select[Table[FromDigits[Join[IntegerDigits[1], IntegerDigits[Prime[n]]]], {n, 300}], PrimeQ]
Select[Table[10^IntegerLength[p]+p, {p, Prime[Range[200]]}], PrimeQ] (* Harvey P. Dale, Oct 17 2021 *)
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PROG
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(Magma) [k: p in PrimesUpTo(1500) | IsPrime(k) where k is Seqint(Intseq(p) cat [1])];
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CROSSREFS
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Cf. A039790 (primes prefixed by 1).
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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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