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Search: id:A134873
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| A134873 |
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Primes p with the property that the sum of the digits of the product of the digits of p is also a prime number. |
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+0
1
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| 2, 3, 5, 7, 13, 17, 31, 37, 43, 71, 73, 113, 127, 131, 137, 151, 173, 211, 223, 257, 271, 277, 281, 311, 317, 431, 457, 523, 541, 547, 557, 577, 727, 757, 821, 853, 1117, 1151, 1171, 1187, 1217, 1223, 1277, 1427, 1451, 1481, 1511, 1523
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Erich Leistenschneider, Table of n, a(n) for n = 1..4095
Erich Lestenschneider's Article about this sequence (in Portuguese).
Erich Leistenschneider, Program used to generate the sequence (Linux)
Erich Leistenschneider, First 4095 numbers of the sequence
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EXAMPLE
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2531 is a member of this sequence because it is a prime number and the product of its digits is 2*5*3*1 = 30, and the sum of the digits of this result is 3+0 = 3, which is also a prime number.
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MAPLE
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a:=proc(n) local dn, pr, dpr: dn:=convert(n, base, 10): pr:=mul(dn[i], i=1..nops(dn)): dpr:=convert(pr, base, 10): if isprime(n)=true and isprime(add(dpr[j], j= 1..nops(dpr)))=true then n else end if end proc: seq(a(n), n=1..1600); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 01 2008
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CROSSREFS
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Adjacent sequences: A134870 A134871 A134872 this_sequence A134874 A134875 A134876
Sequence in context: A009571 A087520 A117159 this_sequence A118724 A046732 A046703
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KEYWORD
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nonn,base
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AUTHOR
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Erich Leistenschneider (el(AT)erichl.net), Feb 01 2008
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