Let m be an integer . Let us say that m is a SPA number if there are positive
whole numbers k and j such that
m = (mk + mj) / 2.
Find all SPA numbers.
With k>=j, these are some special cases, maybe all cases:
1) m=0
2) m=1
3) k=j
4) j=2 and k=3 and m=-2 (corrected via Ady)
5) j and k both odd or both even, and m=-1
Edited on August 4, 2019, 6:32 pm