I’m not sure but could it be because, in your first truth table, you assumed the truth value of (a OR b) -> c to be true and you are finding the truth values of c that correspond with pairs of values of a and b?

However, in the second table you are finding the truth values of ~(a OR b) OR c that correspond with truth values of c as well as a and b so just like you said, you cannot compare the two tables you present above.

To get the truth table for the proposition (a OR b) -> c, you would find the corresponding truth values to those of a, b and c (like you did in the first table). Something like this:

A B C   A OR B   (A OR B) -> C
000       0             1
001       0             1
010       1             0
011       1             1
100       1             0
101       1             1
110       1             0
111       1             1

since it’s possible for the conditional proposition to be false (i.e. if either A or B are true yet C is false)

Afaik they are equivalent since using the truth table of a conditional A->B, it’s false when A is true but B is false (like how a philosophical argument is invalid if the premise A is true yet the conclusion B is false) so ~(A->B) = A and ~B and A->B = ~A or B. Were you asking about something else?

is that danish

Is guix pull still slow? That was a problem I and a few others had a while back.

I don’t think that would work. You just use the fact that the integral from negative to positive infinity of sin(x)/x is pi, so from 0 to infinity it is pi/2, which you can derive from using Feynman’s trick for computing weird integrals like these.