How many integers from 1 to 40 can you form using all 4 digits 2, 0, 1, and 7 exactly once each; the operators
+, –, ×, /, ^, concatenation and ! ?
Any number of parenthesis may be used.
Examples:
1=217^0;
2=2+0*17;
3=21/7+0
...
etc
Team work (adding so far unresolved numbers ) encouraged.
(In reply to
re(2): computer results (spoilers) extended by Charlie)
If we add subfactorial as a use of ! then 38 and 44 also become possible:
38 = (7-!2)!! - 10
44 = !(7-2)+0*1