a(n) = 1 + (n-1) + (n-2)*[(n-3)/2] + (n-3)*[(n-4)/2]*[(n-5)/3] + (n-4)*[(n-5)/2]*[(n-6)/3]*[(n-7)/4] +... where [x] = floor(x), with summation extending over the initial [n/2+1] products only.
A207644
a(n) = 1 + (n-1) + (n-2)*[(n-3)/2] + (n-3)*[(n-4)/2]*[(n-5)/3] + (n-4)*[(n-5)/2]*[(n-6)/3]*[(n-7)/4] +... where [x] = floor(x), with summation extending over the initial [n/2+1] products only.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =8a(6) =10a(7) =17a(8) =30a(9) =42a(10) =55a(11) =116a(12) =172a(13) =220a(14) =391a(15) =683a(16) =1024a(17) =1616a(18) =2050a(19) =3675a(20) =6520a(21) =9504a(22) =12505a(23) =22421a(24) =35572a(25) =56918a(26) =85701a(27) =138110a(28) =202765a(29) =326231
External references
- oeis: A207644