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A342406
Primes p such that the number of ways to write p = 2*q + r with q and r prime is a prime.
1
11, 13, 19, 23, 31, 41, 53, 59, 61, 67, 79, 89, 103, 139, 167, 179, 193, 199, 241, 251, 257, 277, 347, 367, 373, 409, 461, 463, 467, 479, 523, 541, 563, 601, 613, 641, 653, 691, 719, 743, 811, 823, 853, 881, 887, 937, 947, 977, 1039, 1063, 1087, 1117, 1129, 1151, 1223, 1249, 1259, 1277, 1283
OFFSET
1,1
COMMENTS
Primes prime(k) such that A103274(k) is prime.
LINKS
EXAMPLE
a(3) = 19 because there are 2 ways: 19 = 2*3+13 = 2*7+5, and 2 is prime.
MAPLE
filter:= proc(p) local q, count;
q:= 1; count:= 0;
do
q:= nextprime(q);
if 2*q >= p then return isprime(count) fi;
if isprime(p-2*q) then count:= count+1 fi
od
end proc:
select(filter, [seq(ithprime(i), i=1..1000)]);
CROSSREFS
Cf. A103274.
Sequence in context: A188677 A068801 A215504 * A109650 A284037 A338570
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Mar 11 2021
STATUS
approved