Binomial Theorem
\[ \large \sum_{k=0}^n \left[ (-1)^k \dbinom{n}{k} (n-k)^n \right] = \ ? \]
by
Gokul Kumar
\[ \large\displaystyle \sum_{k=1}^{504} \left ( 4k-1 \right ) \binom{2015}{4k-1} \]
If the sum above can be written as \( p.q^{r} \), where \(p\), \(q\) and \(r\) are positive integers with \(q\) being a prime.
Evaluate \( p+q+r \).
Image Credit: Wikimedia TED-43.
by
uzumaki nagato tenshou u…
Let a natural number \( n \) be good if there exist two distinct non-integral real numbers \( a \) and \( b \) such that \( a^k - b^k \) is an integer for all \( 1 \leq k \leq n \).
Find the number of natural numbers which are not good.
by
Siddhartha Srivastava
Compute the remainder when \[ \dbinom {2014}{1} + \dbinom {2014}{4} + \dbinom {2014}{7} + \cdots + \dbinom {2014}{2014} \] is divided by \( 1000 \).
by
Ahaan Rungta
Find the number of odd coefficients in the expansion of \( (a + b)^{2015}. \)
by
Zawad Abdullah