a(n) = A051612(n)*A065387(n) = sigma(n)^2-phi(n)^2, where A051612(n) = sigma(n) - phi(n) and A065387(n) = sigma(n) + phi(n).
A077101
a(n) = A051612(n)*A065387(n) = sigma(n)^2-phi(n)^2, where A051612(n) = sigma(n) - phi(n) and A065387(n) = sigma(n) + phi(n).
Terms
- a(0) =0a(1) =8a(2) =12a(3) =45a(4) =20a(5) =140a(6) =28a(7) =209a(8) =133a(9) =308a(10) =44a(11) =768a(12) =52a(13) =540a(14) =512a(15) =897a(16) =68a(17) =1485a(18) =76a(19) =1700a(20) =880a(21) =1196a(22) =92a(23) =3536a(24) =561a(25) =1620a(26) =1276a(27) =2992a(28) =116a(29) =5120
External references
- oeis: A077101