So:
* There are $140$ numbers $1\le a,b,c,d\le 6$ such that $a+b+c+d=13$
* There are $11$ numbers $1\le a\le b\le c\le d\le 6$ such that $a+b+c+d=13$
* There are $3780$ numbers $1\le a\le b\le c\le d\le 50$ such that $a+b+c+d=100$
* There are $83153$ numbers $1\le a,b,c,d\le 50$ such that $a+b+c+d=100$