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A200145
Primitive (squarefree) elements of A199745.
1
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
1,1
LINKS
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*)
CROSSREFS
Intersection of A199745 and A005117.
Sequence in context: A252547 A211601 A199745 * A179271 A118576 A259413
KEYWORD
nonn
AUTHOR
Ray Chandler, Nov 14 2011
STATUS
approved