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A172458 Nonprimes n such that exactly one of 2n-1 and 2n+1 is prime. 1
1, 4, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 27, 33, 34, 35, 39, 40, 42, 44, 45, 48, 49, 50, 52, 55, 56, 57, 63, 64, 65, 66, 68, 70, 74, 76, 78, 81, 82, 84, 86, 87, 91, 95, 98, 100, 105, 106, 111, 112, 115, 116, 117, 119, 121, 125, 126, 128, 129, 132, 134, 136, 138, 140 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..64.

CROSSREFS

Sequence in context: A029886 A102218 A257586 * A175226 A057166 A230854

Adjacent sequences:  A172455 A172456 A172457 * A172459 A172460 A172461

KEYWORD

nonn,easy,less

AUTHOR

Juri-Stepan Gerasimov, Feb 03 2010

EXTENSIONS

Edited by Charles R Greathouse IV, Mar 25 2010

STATUS

approved

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Last modified November 13 13:15 EST 2018. Contains 317149 sequences. (Running on oeis4.)