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A153167 Numbers n such that n+2 is not a Chen prime. 1
2, 4, 6, 7, 8, 10, 12, 13, 14, 16, 18, 19, 20, 22, 23, 24, 25, 26, 28, 30, 31, 32, 33, 34, 36, 37, 38, 40, 41, 42, 43, 44, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 83, 84, 85, 86, 88, 89, 90 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Contains all strictly positive even numbers A005843.

For each odd k>1 we can accumulate the numbers == k^2-2 (mod 2k) in a row, the last entry equal to A073577(k):

7; (k=3)

13, 23; (k=5)

19, 33, 47; (k=7)

25, 43, 61, 79; (k=9)

31, 53, 75, 97, 119; (k=11)

7, 63, 89, 115, 141, 167; (k=13)

43, 73, 103, 133, 163, 193,223; (k=17)

49, 83, 17, 151,185, 219, 253, 287; (k=19)

Each element T of this table has the format T= k^2-2-j*2*k, so T+2 is of the form k*(k-2*j), therefore not prime, and consequently all elements T are in the sequence.

LINKS

Table of n, a(n) for n=1..71.

CROSSREFS

Cf. A109611, A040976, A073577, A067076.

Sequence in context: A024413 A153347 A330945 * A227187 A047237 A285520

Adjacent sequences:  A153164 A153165 A153166 * A153168 A153169 A153170

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Dec 20 2008

EXTENSIONS

Edited, 41, 59 (see A102540) etc. inserted by R. J. Mathar, Oct 16 2009

STATUS

approved

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Last modified May 16 13:13 EDT 2021. Contains 343947 sequences. (Running on oeis4.)