count,expression,blocks,years,meaning
First sequence,76 + 1 = 77,77,5390,Left outer blocks and the common center.
Second sequence,1 + 76 = 77,77,5390,The common center and right outer blocks.
Common center,1 × 70,1,70,The same block belongs to both sequences.
Combined extent,77 + 77 − 1 = 153,153,10710,Shared center counted once.
Sum of sequence lengths,77 + 77 = 154,154,10780,"Shared center counted in each component; aggregate, not extra elapsed time."