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 A086289 #10 Jan 06 2020 09:13:55 %S A086289 0,1,1,2,1,2,1,3,2,2,3,2,2,4,3,3,2,4,2,3,3,3,5,2,4,4,3,3,5,2,3,4,4,4, %T A086289 3,6,3,5,3,5,4,4,4,6,3,4,3,5,5,5,3,4,7,4,4,6,3,4,6,5,5,3,5,4,7,4,5,4, %U A086289 6,6,4,6,5,3,4,5,8,5,5,7,4,5,4,7,6,6,3,4,6,4,5,8,5,6,5,5,7,4,7,5 %N A086289 Total number of prime factors of 7-smooth numbers. %H A086289 Amiram Eldar, <a href="/A086289/b086289.txt">Table of n, a(n) for n = 1..10000</a> %F A086289 a(n) = A001222(A002473(n)). %F A086289 A086290(n) <= A086291(n) <= a(n). %t A086289 PrimeOmega[Select[Range[500], Max[Transpose[FactorInteger[#]][[1]]] <= 7 &]] (* _Amiram Eldar_, Jan 06 2020 after G. C. Greubel at A086288 *) %Y A086289 Cf. A001222, A002473, A086288, A086290, A086291. %K A086289 nonn %O A086289 1,4 %A A086289 _Reinhard Zumkeller_, Jul 15 2003