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A124518 Numbers k such that 10k-1 and 10k+1 are twin primes. 10
3, 6, 15, 18, 24, 27, 42, 57, 60, 66, 81, 102, 105, 123, 129, 132, 162, 195, 213, 231, 234, 255, 273, 279, 297, 300, 312, 330, 333, 336, 339, 354, 393, 402, 405, 423, 426, 465, 480, 501, 510, 528, 552, 564, 585, 588, 609, 627, 630, 636, 645, 657, 666, 669, 678 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are divisible by 3. - Robert Israel, Apr 07 2019

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

select(t -> isprime(10*t+1) and isprime(10*t-1), [seq(i, i=3..1000, 3)]); # Robert Israel, Apr 07 2019

MATHEMATICA

Select[Range[678], And @@ PrimeQ[{-1, 1} + 10# ] &] (* Ray Chandler, Nov 16 2006 *)

CROSSREFS

Cf. A040040, A045753, A002822, A124065, A124519-A124522, A063983.

Sequence in context: A224864 A176547 A310125 * A160724 A212060 A249246

Adjacent sequences:  A124515 A124516 A124517 * A124519 A124520 A124521

KEYWORD

nonn

AUTHOR

Artur Jasinski, Nov 04 2006

STATUS

approved

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Last modified July 29 13:28 EDT 2021. Contains 346346 sequences. (Running on oeis4.)