cp's OEIS Frontend

A076764 n such that Omega(n-1) < Omega(n) < Omega(n+1), where Omega(m) = the number of prime factors of m, counting multiplicity.

%I A076764 #11 Oct 29 2018 02:26:08
%S A076764 62,63,74,188,194,195,207,242,255,275,278,279,314,363,374,398,399,404,
%T A076764 422,423,455,458,483,494,495,524,539,614,615,662,663,674,692,728,734,
%U A076764 735,747,758,759,764,782,783,854,867,890,927,935,975,998,999
%N A076764 n such that Omega(n-1) < Omega(n) < Omega(n+1), where Omega(m) = the number of prime factors of m, counting multiplicity.
%H A076764 Robert Israel, <a href="/A076764/b076764.txt">Table of n, a(n) for n = 1..10000</a>
%e A076764 Omega(61) = 1 < Omega(62) = 2 < Omega(63) = 3, so 62 is a 1-apex of Omega.
%p A076764 Res:= NULL: a:= numtheory:-bigomega(1): b:= numtheory:-bigomega(2):
%p A076764 for n from 3 to 1001 do
%p A076764   c:= numtheory:-bigomega(n);
%p A076764   if a < b and b < c then Res:= Res, n-1 fi;
%p A076764   a:= b; b:= c;
%p A076764 od:
%p A076764 Res; # _Robert Israel_, Oct 28 2018
%t A076764 Select[Range[3, 10^3], Omega[ # - 1] < Omega[ # ] < Omega[ # + 1] &]
%t A076764 Flatten[Position[Partition[PrimeOmega[Range[1000]],3,1],_?(Min[ Differences[ #]]>0&),{1},Heads->False]]+1 (* _Harvey P. Dale_, Nov 28 2015 *)
%Y A076764 Cf. A001222, A097619.
%K A076764 nonn
%O A076764 1,1
%A A076764 _Joseph L. Pe_, Nov 13 2002
%E A076764 Edited by _Robert Israel_, Oct 28 2018