Search: id:A000977
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%I A000977
%S A000977 30,42,60,66,70,78,84,90,102,105,110,114,120,126,130,132,138,140,150,
%T A000977 154,156,165,168,170,174,180,182,186,190,195,198,204,210,220,222,228,
%U A000977 230,231,234,238,240,246,252,255,258,260,264,266,270,273
%N A000977 Numbers that are divisible by at least three different primes.
%C A000977 a(n+1)-a(n) seems bounded and sequence appears to give n such that the 
               number of integers of the form nk/(n+k) k>=1 is not equal to sum{ 
               d | n, omega(d) } (i.e. n such that A062799(n) is not equal to A063647(n) 
               ) - Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 27 2002
%D A000977 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, 
               National Bureau of Standards Applied Math. Series 55, 1964 (and various 
               reprintings), p. 844.
%H A000977 M. Abramowitz and I. A. Stegun, eds., <a href="http://www.nrbook.com/
               abramowitz_and_stegun/">Handbook of Mathematical Functions</a>, National 
               Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 
               [alternative scanned copy].
%t A000977 DeleteCases[Table[If[Count[PrimeQ[Divisors[i]], True] >= 3, i, 0], {i, 
               1, 274}], 0]
%Y A000977 Cf. A033992, A007774, A000961, A033993, A051270.
%Y A000977 Sequence in context: A090790 A090800 A114816 this_sequence A033992 A091454 
               A136152
%Y A000977 Adjacent sequences: A000974 A000975 A000976 this_sequence A000978 A000979 
               A000980
%K A000977 nonn,easy
%O A000977 1,1
%A A000977 N. J. A. Sloane (njas(AT)research.att.com).
%E A000977 More terms from Vit Planocka (planocka(AT)mistral.cz), Sep 17 2002

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