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%I #10 Nov 08 2018 03:27:18
%S 13,29,31,41,47,61,67,71,83,97,157,193,229,241,271,283,373,397,409,
%T 431,449,467,503,587,601,607,761,787,929,971,991,1039,1087,1091,1163,
%U 1181,1213,1217,1237,1249,1289,1291,1307,1423,1453,1471,1511,1543,1553,1559,1627,1657,1741,1811,1847,1867,1973,1999
%N Primes such that p + digitsum(p, base 8) is again a prime.
%C 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.
%H Robert Israel, <a href="/A320868/b320868.txt">Table of n, a(n) for n = 1..10000</a>
%p digsum:= proc(n,b) convert(convert(n,base,b),`+`) end proc:
%p select(p -> isprime(p) and isprime(p+digsum(p,8)), [seq(i,i=3..10000,2)]); # _Robert Israel_, Nov 07 2018
%o (PARI) forprime(p=1,1999,isprime(p+sumdigits(p,8))&&print1(p","))
%Y 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).
%K nonn,base
%O 1,1
%A _M. F. Hasler_, Nov 06 2018
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