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 A178065 Number of 1's in binary representation of n-th semiprime. 2
 1, 2, 2, 2, 3, 4, 3, 3, 3, 3, 2, 2, 3, 3, 4, 4, 3, 4, 5, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 5, 5, 5, 6, 4, 6, 5, 5, 6, 5, 5, 6, 2, 3, 3, 4, 4, 5, 3, 3, 5, 5, 6, 3, 4, 4, 4, 4, 6, 5, 6, 3, 4, 4, 5, 5, 5, 4, 5, 5, 6, 5, 5, 6, 6, 4, 6, 6, 7, 6, 7, 7, 3, 3, 3, 4, 3, 4, 6, 3, 4, 5, 4, 5, 5, 5, 6, 4, 5, 5, 7, 3, 4, 4, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE a(1)=1 because the first semiprime is 4 = 100_2. a(2)=2 because the second semiprime is 6 = 110_2. PROG (PARI) lista(nn) = {for (n=2, nn, if (bigomega(n)==2, print1(norml2(binary(n)), ", ")); ); } \\ Michel Marcus, Jun 05 2013 CROSSREFS Cf. A001358, A014499. Sequence in context: A281945 A163107 A275840 * A057748 A057747 A281965 Adjacent sequences:  A178062 A178063 A178064 * A178066 A178067 A178068 KEYWORD nonn,base,easy AUTHOR Juri-Stepan Gerasimov, May 18 2010 EXTENSIONS a(56) corrected by R. J. Mathar, May 23 2010 STATUS approved

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Last modified July 17 02:10 EDT 2019. Contains 325092 sequences. (Running on oeis4.)