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 A054011 #9 Oct 27 2023 22:00:46 %S A054011 8,9,10,12,14,18,22,24,25,26,28,30,32,34,35,36,38,40,44,46,48,49,52, %T A054011 54,55,58,60,62,63,64,65,66,68,72,74,76,77,78,80,81,82,84,85,86,88,90, %U A054011 91,92,94,95,96,98,99,100,102,104,106,108,110,112,114,115,116,117,118,119 %N A054011 n is not divisible by the number of its proper divisors. %H A054011 Amiram Eldar, <a href="/A054011/b054011.txt">Table of n, a(n) for n = 1..10000</a> %p A054011 with(numtheory): [seq(`if`(i mod (tau(i)-1) <> 0,i,print( )), i=2..190)]; %t A054011 Select[Range[2, 120], ! Divisible[#, DivisorSigma[0, #] - 1] &] (* _Amiram Eldar_, Aug 28 2019 *) %Y A054011 Cf. A000005, A032741, A054009, A054012. %K A054011 nonn %O A054011 1,1 %A A054011 _Asher Auel_, Jan 17 2000