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 A137491 #20 May 05 2023 10:07:40 %S A137491 960,1344,1728,2112,2240,2496,3264,3520,3648,4160,4416,4928,5440,5568, %T A137491 5824,5832,5952,6080,7104,7290,7360,7616,7872,8000,8256,8512,9024, %U A137491 9152,9280,9920,10176,10206,10304,11328,11712,11840,11968,12864,12992,13120 %N A137491 Numbers with 28 divisors. %C A137491 Maple implementation: see A030513. %C A137491 Numbers of the form p^27 (subset of A122968), p*q^13, p*q*r^6 (A179672) or p^3*q^6 (A179694), where p, q and r are distinct primes. - _R. J. Mathar_, Mar 01 2010 %H A137491 T. D. Noe, <a href="/A137491/b137491.txt">Table of n, a(n) for n = 1..1000</a> %F A137491 A000005(a(n)) = 28. %p A137491 with(numtheory): A137491:=n->`if`(tau(n)=28,n,NULL): seq(A137491(n), n=1..15000); # _Wesley Ivan Hurt_, Sep 18 2014 %t A137491 Select[Range[30000],DivisorSigma[0,#]==28&] (* _Vladimir Joseph Stephan Orlovsky_, May 06 2011 *) %o A137491 (PARI) is(n)=numdiv(n)==28 \\ _Charles R Greathouse IV_, Jun 19 2016 %Y A137491 Cf. A030513-A030516, A030626, A030627, A030634-A030638, A005179, A003680, A096932, A061286, A061283. %K A137491 nonn %O A137491 1,1 %A A137491 _R. J. Mathar_, Apr 22 2008