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 A055720 #14 Mar 12 2020 07:23:29 %S A055720 3,4,10,15,28,35,54,55,63,64,65,85,95,98,100,115,125,135,144,145,147, %T A055720 155,156,175,176,185,189,205,215,234,235,245,260,265,295,297,305,335, %U A055720 336,351,355,364,365,395,400,408,415,416,445,459,485 %N A055720 Numbers k such that d(k)+1 | k. %C A055720 Integers divisible by 1 more than the number of their divisors. The only prime is 3. %C A055720 These numbers cannot be very orderly numbers (A167409). - _T. D. Noe_, Nov 13 2009 %H A055720 Amiram Eldar, <a href="/A055720/b055720.txt">Table of n, a(n) for n = 1..10000</a> %t A055720 Select[Range[1000], Mod[ #, 1 + DivisorSigma[0, # ]] == 0 &] %o A055720 (PARI) isok(k) = Mod(k, numdiv(k)+1) == 0; \\ _Michel Marcus_, Mar 12 2020 %Y A055720 Cf. A000005, A167409. %K A055720 nonn %O A055720 1,1 %A A055720 _Robert G. Wilson v_, Jun 09 2000 %E A055720 Edited by _T. D. Noe_, Nov 13 2009