a(1) = 1, a(n) = Sum_{k=1..n-1} ((6^k - 1)/5)*a(k).
A015507
a(1) = 1, a(n) = Sum_{k=1..n-1} ((6^k - 1)/5)*a(k).
Terms
- a(0) =1a(1) =1a(2) =8a(3) =352a(4) =91520a(5) =142405120
External references
- oeis: A015507
A015507
a(1) = 1, a(n) = Sum_{k=1..n-1} ((6^k - 1)/5)*a(k).