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 A119239 #19 Jul 21 2025 13:12:05
%S A119239 1,3,9,15,45,105,315,945,1575,2835,3465,10395,17325,31185,45045,
%T A119239 135135,225225,405405,675675,2027025,2297295,3828825,6891885,11486475,
%U A119239 34459425,43648605,72747675,130945815,218243025,654729075,1003917915,1527701175
%N A119239 Oddly superabundant numbers: odd n with sigma(n)/n > sigma(k)/k for all odd k < n.
%C A119239 Every oddly colossally abundant number (A110464) is in this sequence.
%C A119239 a(8) = 945 is the first term with abundancy > 2, a(41) = 1018976683725 is the first term with abundancy > 3, and a(141) = 1853070540093840001956842537745897243375 is the first term with abundancy > 4. See A119240. - _Antti Karttunen_, Jul 21 2025
%H A119239 T. D. Noe, <a href="/A119239/b119239.txt">Table of n, a(n) for n = 1..1000</a>
%H A119239 Richard Laatsch, <a href="http://www.jstor.org/stable/2690424">Measuring the abundancy of integers</a>, Mathematics Magazine 59 (2) (1986) 84-92.
%H A119239 Walter Nissen, <a href="http://upforthecount.com/math/abundance.html">Abundancy : Some Resources </a>
%t A119239 rec=0; lst={}; Do[abun=DivisorSigma[1,n]/n; If[abun>rec, rec=abun; AppendTo[lst,n]], {n,1,10^6,2}]; lst
%o A119239 (PARI) r=0;forstep(n=1,1e6,2,t=sigma(n)/n;if(t>r,r=t;print1(n", "))) \\ _Charles R Greathouse IV_, Nov 27 2013
%Y A119239 Cf. A004394 (superabundant numbers), A005231 (odd abundant numbers), A053624 (highly composite odd numbers), A119240.
%Y A119239 Cf. also A171929, A228059, A386423.
%K A119239 nonn
%O A119239 1,2
%A A119239 _T. D. Noe_, May 09 2006
%E A119239 Definition clarified by _Jonathan Sondow_, Dec 08 2011