a(n) = sigma(3*a(n-1)) for n>1 with a(1)=1.
A180708
a(n) = sigma(3*a(n-1)) for n>1 with a(1)=1.
Terms
- a(0) =1a(1) =4a(2) =28a(3) =224a(4) =2016a(5) =20160a(6) =243840a(7) =2545920a(8) =30905280a(9) =388908036a(10) =3622707200a(11) =44117911764a(12) =387754160640
External references
- oeis: A180708