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A175648 Semiprimes m such that m+4 is also semiprime. 8
6, 10, 21, 22, 34, 35, 51, 58, 65, 82, 87, 91, 111, 115, 118, 119, 129, 141, 142, 155, 183, 201, 202, 205, 209, 213, 214, 215, 217, 249, 274, 287, 291, 295, 298, 299, 301, 305, 319, 323, 335, 358, 361, 377, 382, 391, 394, 403, 407, 411, 413, 447, 454, 469, 478 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Zak Seidov, Table of n, a(n) for n = 1..10000

MAPLE

select(t -> numtheory:-bigomega(t)=2 and numtheory:-bigomega(t+4)=2, [$1..1000]); # Robert Israel, Feb 12 2015

MATHEMATICA

Select[Range@ 480, And[PrimeOmega@ # == 2, PrimeOmega[# + 4] == 2] &] (* Michael De Vlieger, Dec 09 2015 *)

PROG

(PARI) isok(n) = (bigomega(n) == 2) && (bigomega(n+4) == 2); \\ Michel Marcus, Feb 12 2015

CROSSREFS

Cf. A001358, A001359, A175612.

Sequence in context: A065758 A254028 A085274 * A178661 A190273 A030007

Adjacent sequences:  A175645 A175646 A175647 * A175649 A175650 A175651

KEYWORD

nonn,easy

AUTHOR

Juri-Stepan Gerasimov, Aug 02 2010

EXTENSIONS

Corrected (309 removed) by R. J. Mathar, Aug 03 2010

Definition corrected by Zak Seidov, Feb 12 2015

STATUS

approved

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Last modified August 18 08:57 EDT 2019. Contains 326077 sequences. (Running on oeis4.)