Smallest number m such that GCD(a+b,a-b) = n, where a = sigma(m) and b = phi(m).

Terms

a(0) =4a(1) =1a(2) =18a(3) =21a(4) =200a(5) =14a(6) =3364a(7) =12a(8) =722a(9) =328a(10) =9801a(11) =42a(12) =25281a(13) =116a(14) =1800a(15) =15a(16) =36992a(17) =810a(18) =4414201a(19) =88a(20) =196a(21) =29161a(22) =541696a(23) =35a(24) =2928200a(25) =1413a(26) =103968a(27) =284a(28) =98942809a(29) =488