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

Terms

a(0) =1a(1) =1a(2) =-5a(3) =9a(4) =-4a(5) =-5a(6) =12a(7) =-4a(8) =25a(9) =-15a(10) =26a(11) =-45a(12) =58a(13) =-44a(14) =20a(15) =-4a(16) =21a(17) =25a(18) =-6a(19) =26a(20) =-60a(21) =82a(22) =-59a(23) =20a(24) =5a(25) =21a(26) =-125a(27) =153a(28) =-124a(29) =75