a(n) = ((1+(-1)^n)*T(n+1) + (1-(-1)^n)*S(n))/2, where T(n) = tribonacci numbers A000073, S(n) = generalized tribonacci numbers A001644.

A075536

a(n) = ((1+(-1)^n)*T(n+1) + (1-(-1)^n)*S(n))/2, where T(n) = tribonacci numbers A000073, S(n) = generalized tribonacci numbers A001644.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =7a(4) =4a(5) =21a(6) =13a(7) =71a(8) =44a(9) =241a(10) =149a(11) =815a(12) =504a(13) =2757a(14) =1705a(15) =9327a(16) =5768a(17) =31553a(18) =19513a(19) =106743a(20) =66012a(21) =361109a(22) =223317a(23) =1221623a(24) =755476a(25) =4132721a(26) =2555757a(27) =13980895a(28) =8646064a(29) =47297029

External references