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 A171995 Twin natural nonprimes with nonprime number of prime factors. 0
 1, 625, 1715, 1925, 2125, 2875, 2975, 3575, 3773, 4165, 4225, 4235, 4625, 5125, 5375, 5425, 5635, 5831, 5875, 5915, 6517, 6625, 7007, 7225, 7315, 7375, 7595, 7625, 7735, 7889, 7975, 8075, 8225, 8281, 8855, 8875, 9025, 9425, 9775, 9875, 10045, 10075 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Intersection of A171697 and A167175. [From R. J. Mathar, Mar 29 2010] LINKS EXAMPLE a(1)=1(without prime factors), a(2)=625(=5*5*5*5), a(3)=1715(=5*7*7*7). PROG (PARI) isA171995(n)=n>0&!isprime(n)&((n%6==1&!isprime(n-2))|(n%6==5&!isprime(n+2)))&!isprime(bigomega(n)) CROSSREFS Cf. A171697. Sequence in context: A186483 A043352 A223183 * A262798 A250431 A046755 Adjacent sequences:  A171992 A171993 A171994 * A171996 A171997 A171998 KEYWORD nonn,less AUTHOR Juri-Stepan Gerasimov, Jan 21 2010 EXTENSIONS Edited and extended by Charles R Greathouse IV, Mar 29 2010 STATUS approved

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Last modified March 20 15:43 EDT 2019. Contains 321345 sequences. (Running on oeis4.)