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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes prime(k) such that A103274(k) is prime.

LINKS

Robert Israel, Table of n, a(n) for n = 1..1000

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

Adjacent sequences:  A342403 A342404 A342405 * A342407 A342408 A342409

KEYWORD

nonn

AUTHOR

J. M. Bergot and Robert Israel, Mar 11 2021

STATUS

approved

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Last modified June 23 18:45 EDT 2021. Contains 345402 sequences. (Running on oeis4.)