You may use the following:
- Addition [e.g. 2+2]
- Subtraction [e.g. 2-2]
- Multiplication [e.g. 2x2]
- Division [e.g. 2/2]
- Decimal point [e.g. 2+.2]
- Exponents [e.g. 22] {tetration is NOT allowed}
- Square roots [e.g. sqrt(2)] {infinite roots sqrt(sqrt(sqrt…sqrt(2))))=1 is NOT allowed}
- Arbitrary roots [e.g. 0.2th root of 2]
- Factorial [e.g. (2+2)!]
- Double factorial [e.g. (2+2)!!]
- Parentheses [e.g. 2/(2+2)]
- Concatenation [e.g. 22+20] {2[0!]=21 is NOT allowed}
- Permutations [e.g. (2+2)P2]
- Combinations [e.g. (2+2)C2]
I’ve got all the numbers from 1-100, except for 54, 67, 68, 69, 79, 82, 83, 84, 86, 87, 93, 97