Step-by-step explanation:looks like it is 7 minus previous number. So, unfortunately 7 does not divide into 85 nicely. 7*12 = 84. So, how every many numbers there are — does it stop at positive numbers only? If not, then it is negative infinity… .
85+78+71+64+57+50+43+36+29+22+15+8+1 = 559
p.s. I tried to be clever with summations (there are 13 numbers) and ran into trouble. Probably the ‘1’ at the end or the 85 at the beginning ... … 7*(summation of 1 to 13) plus an offset to account for the not divisible by 12 exactly. Didn’t work, and it was easier to just do the subtractions and add them together.
