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 A073495 #12 Apr 10 2021 05:50:47 %S A073495 1870,2090,2470,2530,2990,3190,3410,3458,3740,3770,3910,4030,4070, %T A073495 4180,4186,4510,4730,4810,4930,4940,5060,5170,5187,5270,5278,5330, %U A073495 5474,5510,5590,5642,5830,5890,5980,6110,6279,6290,6380,6490,6710,6734,6820,6890 %N A073495 Numbers having exactly three prime gaps in their factorization. %H A073495 Reinhard Zumkeller, <a href="/A073495/b073495.txt">Table of n, a(n) for n = 1..10000</a> %F A073495 A073490(a(n)) = 3. %e A073495 1870 is a term, as 1870 = 2*5*11*17 with three gaps: between 2 and 5, between 5 and 11 and between 11 and 17. %t A073495 q[n_] := SequenceCount[FactorInteger[n][[;; , 1]], {p1_, p2_} /; p2 != NextPrime[p1], Overlaps -> True] == 3; Select[Range[7000], q] (* _Amiram Eldar_, Apr 10 2021*) %o A073495 (Haskell) %o A073495 a073495 n = a073495_list !! (n-1) %o A073495 a073495_list = filter ((== 3) . a073490) [1..] %o A073495 -- _Reinhard Zumkeller_, Dec 20 2013 %Y A073495 Cf. A005117, A073490, A073492, A073493, A073494, A073489. %K A073495 nonn %O A073495 1,1 %A A073495 _Reinhard Zumkeller_, Aug 03 2002