Find-the-value-of-n-such-that-n-n-1-2-k-mod-10-for-n-is-integer-number-

Question Number 135958 by benjo_mathlover last updated on 17/Mar/21

F i n d t h e v a l u e o f n s u c h t h a t

\frac{n (n + 1)}{2} = k (m o d 10) f o r

n i s i n t e g e r n u m b e r