a(n) = (F(3*n+1) - 1)/2, where F=A000045 (the Fibonacci sequence).

A049651

a(n) = (F(3*n+1) - 1)/2, where F=A000045 (the Fibonacci sequence).

Terms

    a(0) =0a(1) =1a(2) =6a(3) =27a(4) =116a(5) =493a(6) =2090a(7) =8855a(8) =37512a(9) =158905a(10) =673134a(11) =2851443a(12) =12078908a(13) =51167077a(14) =216747218a(15) =918155951a(16) =3889371024a(17) =16475640049a(18) =69791931222a(19) =295643364939

External references