Question

find the rules and then complete the sequence
1,2,4,3,9,5,16,7,____,____

please show workings

Answer 1

if the second term has been a 1
I would see a nice pattern

the odd-numbered positions are simply the squares of the natural numbers.
i.e. the first, third, fifth, seventh ...terms are 1,4,9,16,..

then even-numbered positions are simply the odd numbers.
i.e. the second, fourth, 6th, 8th,.. terms are (1),3,5,7,...

if the second is indeed a 2 as you typed it, I see no pattern, that fits all the terms.
Once you get past the second term, the pattern I noted still applies.

Answer 2

4a + 12 = 7a - 9

what is a ?

please show workings