a(n) = floor(tau*a(n-1)) + floor(tau*a(n-2)) with a(0)=0 and a(1)=2.

Terms

a(0) =0a(1) =2a(2) =3a(3) =7a(4) =15a(5) =35a(6) =80a(7) =185a(8) =428a(9) =991a(10) =2295a(11) =5316a(12) =12314a(13) =28525a(14) =66078a(15) =153070a(16) =354588a(17) =821407a(18) =1902799a(19) =4407857a(20) =10210855a(21) =23653572a(22) =54793793a(23) =126930502a(24) =294036085a(25) =681138245a(26) =1577865210a(27) =3655144370a(28) =8467187363a(29) =19614344766