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.
Team work (adding so far unresolved numbers ) encouraged.
(In reply to computer results (spoilers)
Nothing wrong with your program - re existing results.
However, comparing your outputs (both 2017 & 2016) with my p&p results I found mine more extensive:
2017 - going till 50 : only 38 and 44 not resolved
2016 - going till 50 : ALL RESOLVED
All numbers not covered by your software could not be found by present program - but:
THERE IS A CERTAIN OPERATION -KNOWN TO YOU- which allows you to generate the extra numbers, still strictly adhering to the list of symbols permitted by my text.
Leave it to you to ponder about the nature of this "broadening" operator.
Another (not important) remark: several expressions can be presented significantly nicer e.g. 35=7*10/2 .
Edited on June 24, 2017, 12:28 am