In the expansion of (1+x)2(1+y)3(1+z)4(1+w)5, the sum of coefficients of the term of degree 12 is k. Then the value of k13 is
In the expansion of (1+x)n(1+y)n(1+z)n, the sum of coefficients of the terms of degree ‘r’ is
In the expansion of (1+x)n(1+y)n(1+z)n, the sum of the coefficients of the terms of degree r is