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A167631
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Emirps A006567 with a sum of digits and a number of digits which are both primes.
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0
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113, 157, 179, 199, 311, 337, 359, 733, 739, 751, 937, 953, 971, 991, 10039, 10079, 10091, 10253, 10273, 10321, 10343, 10453, 10457, 10459, 10499, 10613, 10639, 10651, 10781, 10853, 10859, 10891, 10909, 11003, 11083, 11159, 11197, 11243
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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113 and 311 are distinct primes, and 3 (number of digits) and 5 (1+1+3) are also primes.
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PROG
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(PARI) sod(n)=my(s=0); while(n>9, s+=n%10; n\=10); s+n
R(n)=my(v=eval(Vec(Str(n))), s=0); forstep(i=#v, 1, -1, s=10*s+v[i]); s
isA167631(n)=my(r); isprime(#Str(n)) && isprime(sod(n)) && isprime(n) && isprime(r=R(n)) && n!=r \\ Charles R Greathouse IV, Nov 10 2009
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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