A133646 a(n)=5*a(n-1)+30*a(n-2) for n>=3, a(0)=1, a(1)=5, a(2)=50 .

1, 5, 50, 400, 3500, 29500, 252500, 2147500, 18312500, 155987500, 1329312500, 11326187500, 96510312500, 822337187500, 7006995312500, 59705092187500, 508735320312500, 4334829367187500, 36936206445312500, 314725913242187500

Offset: 0

Author

Philippe Deléham, Dec 31 2007

Keywords

• easy
• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (5, 30).

Formula

G.f.: (1-5*x^2)/(1-5*x-30*x^2) . a(n) = Sum_{k, 0<=k<=n}A122950(n,k)*5^k .