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A231432 Primes p such that abs(p - 3*k) is also prime, where p is the k-th prime. 1
3, 7, 13, 19, 31, 41, 47, 53, 61, 71, 79, 89, 101, 107, 113, 139, 151, 173, 193, 199, 223, 229, 239, 251, 271, 281, 293, 349, 373, 397, 433, 457, 463, 521, 541, 557, 569, 593, 601, 613, 619, 641, 647, 673, 683, 743, 787, 809, 839, 911, 941, 953, 971, 1013, 1049 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..6400

EXAMPLE

The first prime, 2, is not a term since |2-3*1| = 1.

The second prime, 3, is a term, since |3-2*3| = 3 is a prime.

a(11) = 79 which is the 22nd prime, prime(22)-3*22 = 79-66 = 13 which is also prime.

a(15) = 113 which is the 30th prime, prime(30)-3*30 = 113-90 = 23 which is also prime.

MAPLE

KD := proc() local a, b;  a:= ithprime(n); b:= abs(a-3*n); if isprime(b) then RETURN (a); fi; end: seq(KD(), n=1..500);

MATHEMATICA

KD = Select[Table[{Prime[n], Prime[n] - 3*n}, {n, 200}], PrimeQ[#[[2]]] &]; Transpose[KD][[1]]

PROG

(PARI) k=0; forprime(p=2, 1e3, if(isprime(abs(p-k++*3)), print1(p", "))) \\ Charles R Greathouse IV, Mar 11 2014

CROSSREFS

Cf. A061068 (primes: prime(m) plus its subscript).

Cf. A064402 (numbers n: prime(n)+n is prime).

Cf. A231232 (primes p : p+2*k is also prime).

Cf. A231383 (primes p : p+3*k is also prime).

Sequence in context: A304874 A167473 A256864 * A271981 A103521 A103966

Adjacent sequences:  A231429 A231430 A231431 * A231433 A231434 A231435

KEYWORD

nonn,easy

AUTHOR

K. D. Bajpai, Nov 09 2013

STATUS

approved

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Last modified May 12 10:54 EDT 2021. Contains 343821 sequences. (Running on oeis4.)