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A318292 Prime-indexed primes q such that prime(q) + q + 1 is a prime-indexed prime. 2
5, 109, 1913, 2081, 2351, 2897, 3169, 4027, 4397, 8221, 9461, 9661, 13613, 14969, 17117, 17483, 24133, 28109, 31513, 32969, 47417, 60149, 61627, 73259, 84809, 89213, 105929, 113051, 124121, 143477, 152767, 156671, 159667, 162947, 174893, 209621, 219533, 223637, 241463, 243469, 250307, 263591 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This sequence and the sequence of resulting primes prime(q)+q+1 (17,709, 18433, 20231, 23251, 29269, 32323, 42181, ...) are subsequences of A006450, the prime indexed primes.

LINKS

Table of n, a(n) for n=1..42.

N. Fernandez, An order of primeness, F(p)

N. Fernandez, An order of primeness [cached copy, included with permission of the author]

EXAMPLE

a(1) is 5 because 5 = prime(3) and prime(5) + 5 + 1 = 17 = prime(7), and no smaller prime has this property.

MAPLE

N:=300000:

for n from 1 to N do

if isprime(n) then q:=ithprime(n);

Z:=numtheory[pi](n);

P:=q+n+1;

R:=numtheory[pi](P);

if isprime(Z) and isprime(P) and isprime(R) then print(n);

end if:

end if:

end do:

PROG

(PARI) isok(p) = isprime(p) && isprime(primepi(p)) && isprime(q=prime(p)+p+1) && isprime(primepi(q)); \\ Michel Marcus, Sep 19 2018

CROSSREFS

Cf. A000040, A006450.

Sequence in context: A195561 A142510 A195552 * A012239 A012121 A014180

Adjacent sequences:  A318289 A318290 A318291 * A318293 A318294 A318295

KEYWORD

nonn

AUTHOR

David James Sycamore, Aug 22 2018

STATUS

approved

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Last modified August 11 04:03 EDT 2020. Contains 336421 sequences. (Running on oeis4.)