A338771 Primes p such that A338770(p) is prime.

7, 41, 59, 61, 89, 167, 193, 251, 257, 283, 367, 401, 479, 523, 599, 601, 641, 743, 761, 811, 983, 997, 1087, 1109, 1117, 1201, 1277, 1361, 1429, 1483, 1619, 1741, 1789, 1861, 1889, 1901, 1931, 2237, 2297, 2417, 2609, 2843, 2897, 2939, 2971, 3023, 3121, 3167, 3373, 3413, 3457, 3533, 3719, 3767

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..3790

Example

a(3)=59 is in the sequence because 59 is prime and A338770(59) = 103 is prime.

Maple

filter:= proc(p) local q, v, t;
     t:= 0; q:= 1;
     do
       q:= nextprime(q);
       if 2*q > p then return isprime(t) fi;
       v:= p-2*q;
       if isprime(v) then t:= t+v fi;
     od
end proc:
select(filter, [seq(ithprime(i), i=1..2000)]);

Prog

(PARI) f(n) = my(s=0); forprime(p=0, n\2, if (isprime(q=n-2*p), s+=q)); s; \\ A338770
isok(p) = isprime(p) && isprime(f(p)); \\ Michel Marcus, Nov 08 2020

Crossrefs

Cf. A338770.

Sequence in context: A224718 A374234 A272387 * A161505 A105902 A031909

Adjacent sequences: A338768 A338769 A338770 * A338772 A338773 A338774

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Nov 08 2020

Status

approved