a(n) = 4^n*(1 + (23/8)*n + (9/8)*n^2).
A361609
a(n) = 4^n*(1 + (23/8)*n + (9/8)*n^2).
Terms
- a(0) =1a(1) =20a(2) =180a(3) =1264a(4) =7808a(5) =44544a(6) =240640a(7) =1249280a(8) =6291456a(9) =30932992a(10) =149159936a(11) =707788800a(12) =3313500160a(13) =15334375424a(14) =70262980608a(15) =319169757184
External references
- oeis: A361609