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A320868
Primes such that p + digitsum(p, base 8) is again a prime.
4
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
OFFSET
1,1
COMMENTS
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.
LINKS
MAPLE
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
PROG
(PARI) forprime(p=1, 1999, isprime(p+sumdigits(p, 8))&&print1(p", "))
CROSSREFS
Cf. A047791, A048519 (base 10 analog), A048520, A006378, A107740, A243441 (base 2 analog: p + Hammingweight(p) is prime), A243442 (analog for p - Hammingweight(p)), A320866 (analog for base 4), A320867 (analog for base 6).
Sequence in context: A087593 A158075 A087594 * A347816 A319167 A088909
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Nov 06 2018
STATUS
approved