Numbers n such that sigma(2n+1)=3n.

Terms

a(0) =2a(1) =16a(2) =130a(3) =192a(4) =448a(5) =1120a(6) =13468a(7) =23296a(8) =7176640a(9) =135939072a(10) =581150416a(11) =3259721920a(12) =9517877824a(13) =21538220800