a(1) = 1, a(n) = Sum_{k=1}^{n-1} (5^k - 1)/4 a(k).
A015506
a(1) = 1, a(n) = Sum_{k=1}^{n-1} (5^k - 1)/4 a(k).
Terms
- a(0) =1a(1) =1a(2) =7a(3) =224a(4) =35168a(5) =27501376a(6) =107447876032
External references
- oeis: A015506
A015506
a(1) = 1, a(n) = Sum_{k=1}^{n-1} (5^k - 1)/4 a(k).