Dean is building a tower with blocks as shown in the diagram. the tower shown has three stories
and uses 15 blocks. how many blocks are required for a tower of 80 stories?
a) 400
b) 6399
c) 6496
d) 6560
e) 6723

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?