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for the whole solution n = no. of layers, x = no. on bottom left corner. y = top most no.
for every layer we add x to itself n-1 times.
thus y = (2^(n-1)x) + constant
the constant follows patern- 0, 1, 4, 12, 32...
thus it can be derived as constant at nth layer = (2^(n-2))*(n-1)
thus y = (2^(n-1)x) + (2^(n-2))*(n-1)
= (2^(n-2))*(2x+n-1)
so given the top most no. in a 4 layer triangle, x = (y-12)/8
if the no. steps by 2 every time on bottom layer, it follows the pattern of the 2nd layer. so the apparent bottom left no. will be (x-1)/2 and n increases by 1 for calculations. for a 4 layer triangle with step 2, y = 16*(x-1+4)
= 16x+48
i hope this answers all the questions posed.