A200145 Primitive (squarefree) elements of A199745.

2145, 2730, 4641, 4845, 5005, 5610, 7410, 8778, 9177, 11305, 11730, 13485, 13585, 17017, 20010, 20930, 21489, 21505, 23529, 26445, 29946, 31465, 31857, 32538, 33649, 34410, 35409, 35581, 36685, 38570, 38874, 41106, 42441, 43401, 45066, 46189, 46345, 47730, 49569

Offset: 1

Author

Ray Chandler, Nov 14 2011

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Intersection of A199745 and A005117.

Programs

Maple

Filter:= proc(n) local F;
  F:= ifactors(n)[2];
  if max(seq(f[2],f=F)) > 1 or nops(F) < 4 then return false fi;
  F:= map(t -> t[1],F);
  convert(F,`+`) = 2*(max(F)+min(F));
end proc:
select(Filter,[$1..10^5]); # Robert Israel, Dec 31 2015

Mathematica

Select[Range[50000],Max@@Last/@(fi=FactorInteger[#])==1&&Plus@@(pl=First/@fi)/2==pl[[1]]+pl[[-1]]&] (*Ray Chandler, Nov 14 2011*)