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A138303 Numbers n such that n*(n+1)-1 and n*(n+1)+1 are twin primes and n*(n+3)-1 and n*(n+3)+1 are also twin primes. 3
3, 15, 495, 624, 1308, 1365, 1494, 1659, 1848, 6363, 8064, 12780, 13908, 14013, 16530, 18018, 18654, 28575, 30885, 31020, 38130, 43674, 48735, 50379, 57198, 60915, 61059, 62943, 75768, 76359, 76569, 80949, 81075, 83028, 84045, 86085, 88185, 104664, 105588 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

David A. Corneth, Table of n, a(n) for n = 1..10000 (first 500 terms from Pierre CAMI)

EXAMPLE

3*4=12: 11 and 13 are twin primes; 3*6=18 and 17 and 19 are also twin primes.

PROG

(PARI) isok(n) = isprime(n*(n+1)-1) && isprime(n*(n+1)+1) && isprime(n*(n+3)-1) &&  isprime(n*(n+3)+1); \\ Michel Marcus, Sep 23 2019

CROSSREFS

Subsequence of A088485.

Sequence in context: A193119 A309069 A122579 * A338293 A267096 A217449

Adjacent sequences:  A138300 A138301 A138302 * A138304 A138305 A138306

KEYWORD

nonn

AUTHOR

Pierre CAMI, Mar 13 2008

STATUS

approved

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Last modified December 6 13:45 EST 2021. Contains 349563 sequences. (Running on oeis4.)