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 A086290 #9 Jan 06 2020 08:36:13 %S A086290 0,1,1,2,1,1,1,3,2,1,1,1,1,4,1,1,1,1,2,3,1,1,5,1,2,1,1,1,1,2,1,1,1,1, %T A086290 1,6,1,2,1,1,4,1,1,1,1,2,1,2,1,1,3,1,7,1,1,2,1,1,1,1,1,1,1,1,1,2,2,1, %U A086290 3,1,2,1,5,1,1,1,8,1,1,2,1,1,1,1,2,1,3,1,1,1,1,1,2,2,1,1,3,2,1,1 %N A086290 Minimal exponent in prime factorization of 7-smooth numbers. %H A086290 Amiram Eldar, <a href="/A086290/b086290.txt">Table of n, a(n) for n = 1..10000</a> %F A086290 a(n) = A051904(A002473(n)). %F A086290 a(n) <= A086291(n) <= A086289(n). %t A086290 minExp[1] = 0; minExp[n_] := Min @@ Last /@ FactorInteger[n]; minExp/@Select[Range[500], Max[Transpose[FactorInteger[#]][[1]]] <= 7 &] (* _Amiram Eldar_, Jan 06 2020 *) %Y A086290 Cf. A002473, A051904, A086289, A086291. %K A086290 nonn %O A086290 1,4 %A A086290 _Reinhard Zumkeller_, Jul 15 2003