a(n) = 3^(2*n+1) - 3^(n+1) + 1: The left Aurifeuillian factor of 3^(6*n+3) + 1.
A220978
a(n) = 3^(2*n+1) - 3^(n+1) + 1: The left Aurifeuillian factor of 3^(6*n+3) + 1.
Terms
- a(0) =1a(1) =19a(2) =217a(3) =2107a(4) =19441a(5) =176419a(6) =1592137a(7) =14342347a(8) =129120481a(9) =1162202419a(10) =10460176057a(11) =94142647387a(12) =847287015121
External references
- oeis: A220978