A181959 Number of distinct 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.
9, 48, 236, 1274, 6489, 30229, 142320, 711955, 3601566
Offset: 0
Keywords
Examples
a(1)=48, the distinct values are -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 20 21 24 25 27 28 30 32 35 36 40 42 45 48 49 54 56 63 64 72 81