Smooth out array of increasing numbers

I have array of values like below

[100,190,290,395,500,800,700,800,600,1020]

Here I have sets of numbers with increasing numbers , but here there is two odd numbers when i plot it as graph , 800 and 600 , both should be replaced something like 610 and 900 respectively.

How can I achieve it.

Note : There will be maximum two odd numbers in a row , in total of minumum of 10 numbers