a(n) = F(3) + F(6) + F(9) + ... + F(3n), F(n) = Fibonacci numbers A000045.

A099919

a(n) = F(3) + F(6) + F(9) + ... + F(3n), F(n) = Fibonacci numbers A000045.

Terms

    a(0) =0a(1) =2a(2) =10a(3) =44a(4) =188a(5) =798a(6) =3382a(7) =14328a(8) =60696a(9) =257114a(10) =1089154a(11) =4613732a(12) =19544084a(13) =82790070a(14) =350704366a(15) =1485607536a(16) =6293134512a(17) =26658145586a(18) =112925716858a(19) =478361013020

External references