a(0) = 0, a(n) = -5*a(n/3) if n is divisible by 3, otherwise a(n) = n + a(n-1).

Terms

a(0) =0a(1) =1a(2) =3a(3) =-5a(4) =-1a(5) =4a(6) =-15a(7) =-8a(8) =0a(9) =25a(10) =35a(11) =46a(12) =5a(13) =18a(14) =32a(15) =-20a(16) =-4a(17) =13a(18) =75a(19) =94a(20) =114a(21) =40a(22) =62a(23) =85a(24) =0a(25) =25a(26) =51a(27) =-125a(28) =-97a(29) =-68