I solved them too by taking the formulas I know and then adjusting them to the ones similair by your sequences:
code:
1,3,6,10
y = (number/2) * (first + last)
y = (x/2)(x+1) = (x*x +x)/2
3, 6, 10, 15, 21
y = (x+1)(x+2)/2 = (x*x + 3x + 2)/2
1,2,4,8
y = g ** x
y = 2 ** (x - 1)
8, 16, 32, 64, 128
y = 2 ** (x + 2)
Edit: I assumed y(1) is the first value in both sequences.
Edit2: Power/multiplication typo. I prefer ** for powers.
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