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A064402 Numbers n such that prime(n)+n is a prime, where prime(n) denotes the n-th prime number. 19
1, 2, 4, 6, 18, 22, 24, 26, 32, 34, 42, 48, 66, 70, 72, 82, 92, 96, 98, 100, 102, 104, 106, 108, 114, 116, 126, 130, 144, 150, 152, 158, 172, 180, 200, 202, 204, 206, 218, 222, 228, 236, 270, 282, 290, 300, 312, 322, 324, 328, 330, 350, 352, 356, 362, 378, 384 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = order among the primes of A061067(n).

Except for the first one all terms are even. Conjecture: First differences include all even integers. - Zak Seidov, Nov 10 2013

LINKS

Harry J. Smith, Table of n, a(n) for n=1..1000

FORMULA

a(n) = A061068(n) - A061067(n-1).

A014688(a(n)) = A061068(n). - Zak Seidov, Nov 10 2013

MATHEMATICA

Select[ Range[ 400 ], PrimeQ[ Prime[ # ] + # ] & ]

PROG

(PARI) { n=0; for (m=1, 10^9, if (isprime(prime(m) + m), write("b064402.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 13 2009

(MAGMA) [n: n in [0..500]| IsPrime(NthPrime(n) +n)]; // Vincenzo Librandi, Apr 06 2011

CROSSREFS

Cf. A061067, A061068, A064269.

Sequence in context: A074131 A309282 A019464 * A268577 A075229 A242765

Adjacent sequences:  A064399 A064400 A064401 * A064403 A064404 A064405

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Sep 28 2001

EXTENSIONS

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 08 2007

STATUS

approved

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Last modified October 15 05:43 EDT 2019. Contains 328026 sequences. (Running on oeis4.)