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 A200145 #15 Dec 31 2015 16:23:15 %S A200145 2145,2730,4641,4845,5005,5610,7410,8778,9177,11305,11730,13485,13585, %T A200145 17017,20010,20930,21489,21505,23529,26445,29946,31465,31857,32538, %U A200145 33649,34410,35409,35581,36685,38570,38874,41106,42441,43401,45066,46189,46345,47730,49569 %N A200145 Primitive (squarefree) elements of A199745. %H A200145 Robert Israel, <a href="/A200145/b200145.txt">Table of n, a(n) for n = 1..10000</a> %p A200145 Filter:= proc(n) local F; %p A200145 F:= ifactors(n)[2]; %p A200145 if max(seq(f[2],f=F)) > 1 or nops(F) < 4 then return false fi; %p A200145 F:= map(t -> t[1],F); %p A200145 convert(F,`+`) = 2*(max(F)+min(F)); %p A200145 end proc: %p A200145 select(Filter,[$1..10^5]); # _Robert Israel_, Dec 31 2015 %t A200145 Select[Range[50000],Max@@Last/@(fi=FactorInteger[#])==1&&Plus@@(pl=First/@fi)/2==pl[[1]]+pl[[-1]]&] (*Ray Chandler, Nov 14 2011*) %Y A200145 Intersection of A199745 and A005117. %K A200145 nonn %O A200145 1,1 %A A200145 _Ray Chandler_, Nov 14 2011