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A066725
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Primes p the product of whose digits increased by one is prime.
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3
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2, 11, 23, 29, 41, 43, 47, 61, 67, 89, 149, 163, 167, 211, 223, 227, 229, 233, 251, 257, 263, 269, 281, 349, 367, 383, 419, 431, 433, 439, 463, 491, 521, 523, 569, 587, 613, 617, 631, 643, 659, 661, 673, 761, 769, 821, 827, 857, 883, 887, 929, 941, 967, 1123
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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2 * 2 * 3 + 1 = 13, a prime; since 223 is also prime, it is a term of the sequence.
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MATHEMATICA
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Select[Prime[Range[200]], PrimeQ[Times@@IntegerDigits[#]+1]&] (* Harvey P. Dale, May 09 2012 *)
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PROG
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(PARI) ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) } { n=0; for (m=1, 10^10, if (isprime(ProdD(p=prime(m)) + 1), write("b066725.txt", n++, " ", p); if (n==1000, return)) ) } \\ Harry J. Smith, Mar 19 2010
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CROSSREFS
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KEYWORD
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easy,nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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