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A065439
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Numbers n such that s[n], p[n] and s[n]+p[n] are all prime numbers, where s[n] is the sum of digits of n and p[n] is the product of digits of n.
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0
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12, 21, 1112, 1121, 1211, 2111, 1111111112, 1111111121, 1111111211, 1111112111, 1111121111, 1111211111, 1112111111, 1121111111, 1211111111, 2111111111, 1111111111111112, 1111111111111121, 1111111111111211, 1111111111112111
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| p[n] will always be 2 and s[n] and s[n]+p[n] will always be twin primes.
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LINKS
| A. G. Gevisier, A curiosity about the number 12
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MATHEMATICA
| Do[s = Apply[ Plus, IntegerDigits[n]]; p = Apply[ Times, IntegerDigits[n]]; If[ PrimeQ[s] && PrimeQ[p] && PrimeQ[s + p], Print[n]], {n, 1, 10^7} ]
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CROSSREFS
| Sequence in context: A001292 A162391 A114015 * A031186 A078538 A098955
Adjacent sequences: A065436 A065437 A065438 * A065440 A065441 A065442
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KEYWORD
| base,nonn
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AUTHOR
| Santi Spadaro (spados(AT)katamail.com), Nov 17 2001
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EXTENSIONS
| Comment and more terms from Larry Reeves (larryr(AT)acm.org), Nov 27 2001
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