Combinatorial Equations

This calculator solves equations with combinations, arrangements and permutations where the unknown is a natural number n.

C_n^k = ^n!/_{k! · (n − k)!},   A_n^k = ^n!/_{(n − k)!},   P_n = n!

Example. C(n, 2) = 15: n(n − 1)/2 = 15, so n² − n − 30 = 0 and n = 6. The value −5 does not fit because n is natural.

The calculator finds the roots by testing n from 0 to 150, so it shows the answer but not the algebraic transformation.