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

Terms

a(0) =119a(1) =1559a(2) =2939a(3) =17759a(4) =19919a(5) =32219a(6) =33839a(7) =55964a(8) =71039a(9) =186779a(10) =308039a(11) =511499a(12) =523775a(13) =553499a(14) =699359a(15) =838214a(16) =1048904a(17) =1159379a(18) =1328939a(19) =1333247a(20) =1700039a(21) =2462687a(22) =2703887a(23) =2956079a(24) =3115319a(25) =3561095a(26) =3764207a(27) =3972695a(28) =7625879a(29) =7852919