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 A100363 #6 Aug 03 2014 20:34:14 %S A100363 193,397,454,457,613,614,661,757,758,997,998,1093,1237,1238,1453,1478, %T A100363 1657,1681,1766,2137,2341,2413,2455,2593,2917,2918,2942,2966,3217, %U A100363 3334,3494,3589,4021,4177,4183,4406,4621,5143,5233,5965,6121,6133,6134,6193 %N A100363 Numbers n such that the numbers of divisors of n,n+1 and n+2 are k,2k,4k respectively for some k. %H A100363 Harvey P. Dale, <a href="/A100363/b100363.txt">Table of n, a(n) for n = 1..1000</a> %e A100363 n=193,195,195 have 2,4,8 divisors. %t A100363 d0[x_] :=DivisorSigma[0, x];ta={{0}}; Do[g=n;s=d0[n];s1=d0[n+1];s2=d0[n+2]; If[Equal[s1, 2*s]&&Equal[s2, 4*s], ta=Append[ta, n]; Print[{n, s, s1, s2}]], {n, 1, 10000}];{ta=Delete[ta, 1], g} %t A100363 Flatten[Position[Partition[DivisorSigma[0,Range[6200]],3,1],_?(Length[ Union[ #/{1,2,4}]] == 1&),{1},Heads->False]] (* _Harvey P. Dale_, Aug 03 2014 *) %Y A100363 Cf. A000005, A063446. %K A100363 nonn %O A100363 1,1 %A A100363 _Labos Elemer_, Nov 19 2004