a(n)=Sum((-1)^(i+Floor(n/2))S(2i+e),(i=0,..,Floor(n/2))), where S(n) are generalized Tetranacci numbers (A073817) and e=(1/2)(1-(-1)^n).

A075112

a(n)=Sum((-1)^(i+Floor(n/2))S(2i+e),(i=0,..,Floor(n/2))), where S(n) are generalized Tetranacci numbers (A073817) and e=(1/2)(1-(-1)^n).

Terms

    a(0) =4a(1) =1a(2) =-1a(3) =6a(4) =16a(5) =20a(6) =35a(7) =79a(8) =156a(9) =288a(10) =552a(11) =1077a(12) =2079a(13) =3994a(14) =7696a(15) =14848a(16) =28623a(17) =55159a(18) =106320a(19) =204952a(20) =395060a(21) =761489a(22) =1467815a(23) =2829318a(24) =5453688a(25) =10512308a(26) =20263123a(27) =39058439a(28) =75287564a(29) =145121432

External references