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A320866
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Primes such that p + digitsum(p, base 4) is again a prime.
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5
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5, 7, 13, 17, 19, 37, 59, 67, 97, 127, 173, 193, 223, 233, 277, 359, 379, 439, 499, 563, 569, 599, 607, 631, 653, 691, 733, 769, 811, 821, 829, 877, 919, 929, 937, 967, 1009, 1019, 1087, 1093, 1163, 1193, 1213, 1223, 1229, 1297, 1319, 1373, 1399, 1423, 1481, 1483, 1559, 1571, 1597, 1613, 1619, 1627, 1657, 1699, 1733, 1777
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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 even bases b. See A243441, A320867, A320868 and A048519 for the analog in base 2, 6, 8 and 10, respectively. Also, as in base 10, there are no such primes (except 5 and 7) when + is changed to -, see comment in A243442.
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LINKS
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EXAMPLE
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5 = 4 + 1 = 11[4] (in base 4), and 5 + 1 + 1 = 7 is again prime.
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MATHEMATICA
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Select[Prime[Range[300]], PrimeQ[#+Total[IntegerDigits[#, 4]]]&] (* Harvey P. Dale, Feb 06 2020 *)
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PROG
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(PARI) forprime(p=1, 1999, isprime(p+sumdigits(p, 4))&&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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