# What a familiar progression!

Algebra Level 2

$1 \; , \; \text{\_\_\_\_\_\_} \; , \; \text{\_\_\_\_\_\_} \; , \; \text{\_\_\_\_\_\_} \; , \; \text{\_\_\_\_\_\_} \; , \; 2017$

Brian has written up 6 numbers, where each subsequent number is larger than the one before it, and he plans to add up these numbers.

However, due to his terrible handwriting, he is unable to decipher all but the first and last numbers, as illustrated above.

He does, however, recall that the differences between two consecutive numbers are all the same. Can you help him find the sum of these 6 numbers?

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