G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - 2 * x * (1 + x + x^2 + x^3) * A(x^4))).
A390658
G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - 2 * x * (1 + x + x^2 + x^3) * A(x^4))).
Terms
- a(0) =1a(1) =3a(2) =9a(3) =27a(4) =81a(5) =247a(6) =753a(7) =2295a(8) =6993a(9) =21315a(10) =64969a(11) =198027a(12) =603585a(13) =1839735a(14) =5607537a(15) =17091847a(16) =52096161a(17) =158789763a(18) =483993225a(19) =1475217531a(20) =4496481841a(21) =13705334015a(22) =41774032929a(23) =127327785327a(24) =388096714065
External references
- oeis: A390658