Resolved: How to enter an array of non-adjacent cells as first argument in trend function?

Question:

I want to find the value for A3.
__|_A___
1 | 5
2 | 10
3 | blank
4 | 20
So in A3 I add this:
=trend( {A1,A2,A4}  ,  {1,2,4}  ,  {3}  )
That produces an error.

Answer:

Using INDEX:
=TREND(INDEX(A:A,{1,2,4}),{1,2,4},{3})
enter image description here

If you have better answer, please add a comment about this, thank you!

Source: Stackoverflow.com