How to program a neural network set of numbers => set of numbers?

Question

Neural networks

I have some system whose behavior is described by a vector of numbers.
How should the structure of a neural network look like, which would be trained on a set of such vectors and subsequently be able to restore similar vectors from several known components?
For example, we feed
(a1, a2, a3, ...)
(b1, b2, b3, ...)
...
Then for the vector
(n1, n2, X1, X2, ....)
calculate the unknown X1 and X2 with known n1, n2, n4, n5, etc.