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A320868
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Primes such that p + digitsum(p, base 8) is again a prime.
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4
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13, 29, 31, 41, 47, 61, 67, 71, 83, 97, 157, 193, 229, 241, 271, 283, 373, 397, 409, 431, 449, 467, 503, 587, 601, 607, 761, 787, 929, 971, 991, 1039, 1087, 1091, 1163, 1181, 1213, 1217, 1237, 1249, 1289, 1291, 1307, 1423, 1453, 1471, 1511, 1543, 1553, 1559, 1627, 1657, 1741, 1811, 1847, 1867, 1973, 1999
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OFFSET
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1,1
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COMMENTS
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Such primes exist only for an even base b. See A048519, A243441, A320866 and A320867 for the analog in base 10, 2, 4 and 6, respectively. Also, as in base 10, there are no such primes (except 11 and 13) when + is changed to -, see comment in A243442.
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LINKS
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MAPLE
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digsum:= proc(n, b) convert(convert(n, base, b), `+`) end proc:
select(p -> isprime(p) and isprime(p+digsum(p, 8)), [seq(i, i=3..10000, 2)]); # Robert Israel, Nov 07 2018
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PROG
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(PARI) forprime(p=1, 1999, isprime(p+sumdigits(p, 8))&&print1(p", "))
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CROSSREFS
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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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