This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A175761 #12 Sep 17 2017 21:44:22
%S A175761 1,45,63,75,99,117,135,147,153,165,171,175,207,245,255,261,273,279,
%T A175761 315,325,333,345,351,363,369,375,385,387,399,405,423,435,455,459,475,
%U A175761 477,495,507,531,539,549,561,567,595,603,615,639,651,657,665,675,705,711,715,735
%N A175761 Odd nonprimes such that the arithmetic mean of all prime factors is not an integer.
%C A175761 The presence of 1 (which has no prime factors) is for compatibility with A175352.
%H A175761 G. C. Greubel, <a href="/A175761/b175761.txt">Table of n, a(n) for n = 1..5000</a>
%F A175761 Equals: Intersection of A175352 and A014076.
%e A175761 a(6) = 117 because 117 = 3*3*13 and (3 + 3 + 13)/3 is not an integer.
%t A175761 fQ[n_] := Block[{fi = Flatten[ Table[ #[[1]], {#[[2]]}] & /@ FactorInteger@ n]}, len = Length@ fi; len != 1 && ! IntegerQ[ Plus @@ fi/len]]; Join[{1},Select[1 + 2 Range@ 356, fQ]] (* _Robert G. Wilson v_, Aug 31 2010 *)
%Y A175761 Cf. A141468, A175352.
%K A175761 nonn,easy
%O A175761 1,2
%A A175761 _Juri-Stepan Gerasimov_, Aug 29 2010
%E A175761 Corrected (315, 345 inserted, 355 removed) by _R. J. Mathar_, Aug 30 2010