Number of distinct nonnegative integers that can be generated by an expression containing n binary operators (any of add, subtract, multiply and divide) whose operands are any integer between 1 and 9; parenthesis allowed.
A181960
Number of distinct nonnegative integers that can be generated by an expression containing n binary operators (any of add, subtract, multiply and divide) whose operands are any integer between 1 and 9; parenthesis allowed.
Terms
- a(0) =9a(1) =40a(2) =156a(3) =740a(4) =3668a(5) =16948a(6) =77861a(7) =379084a(8) =1889419
External references
- oeis: A181960