10 11 13 16 20 after what number comes

Answer 1

25....
so umm
10+1 = 11
11+2 = 13
13+3 = 16
16+4 =20
20+5= 25
i hope this is correct

Answer 2

It is correct. Good job!

Answer 3

btw,
term (n) = (1/2)(n^2 - n + 20) , for n as a natural number