Pascal Pyramid
Pascal's Triangle is the following pattern of numbers
1 2 3 4 

Now, consider the Pascal's Pyramid, an extension of Pascal's Triangle. Instead of adding two numbers in the row above, Pascal's Pyramid adds 3 adjacent numbers from the layer above. When viewing from top,
Layer 0 :
1 

Layer 1 :
1 2 

Layer 2 :
1 2 3 

What is the sum of numbers in layer 8?