Hello, today i'm gonna tell ya how to solve this easy task!

We can notice: 1 has places 0,1,3,6,10 etc.
0*8+1 = 1; 1*8+1 = 9; 3*8+1 = 25; 6*8+1 = 49; 10*8+1 = 81; I gave you the advice!

So, it's easy! Good luck!

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