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A179443 Numbers m such that m and 10*m + 1 are both composites. 2
8, 9, 12, 14, 16, 20, 22, 26, 30, 32, 34, 35, 36, 38, 39, 44, 45, 48, 50, 51, 55, 56, 58, 62, 65, 68, 72, 74, 77, 78, 80, 84, 85, 86, 87, 90, 92, 93, 95, 96, 98, 100, 104, 108, 110, 111, 112, 114, 116, 119, 121, 122, 124, 125, 126, 128, 133, 134, 135, 140, 141 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding values of 10*m + 1 are in A179444.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..1000

PROG

(PARI) is(n)={n>1 && !isprime(n) && !isprime(10*n+1)}

select(is, [1..200]) \\ Andrew Howroyd, Jan 04 2020

CROSSREFS

Cf. A179444.

Sequence in context: A168415 A199635 A131864 * A264828 A080756 A304661

Adjacent sequences:  A179440 A179441 A179442 * A179444 A179445 A179446

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jul 14 2010

EXTENSIONS

Terms a(43) and beyond from Andrew Howroyd, Jan 04 2020

STATUS

approved

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Last modified April 13 10:24 EDT 2021. Contains 342935 sequences. (Running on oeis4.)