It's always possible to find another number in any sequence! For example, consider the function:
f(n) = - (19/6)n4 + (175/6)n3 - (235/3)n2 + (421/3)n - 9
n f(n)
1 79
2 141
3 238
4 355
5 401
6 209
Of course, this might not be the sequence the questioner had in mind!