For something this short, just start at the right, times each number by 8 as you go down, then sum (conversely double double double then sum total). Took me about 10s. 00001 00008 00064 00512 04096 32768 = 37449
Given it's 111111 in base 8 (no need to remember geometric progression), it seems somewhat simpler to solve this as (8^6 - 1) / 7 = (2^18 - 1) / 7 = 262143 / 7
Or for anyone that uses computers at any reasonable level, you already know that this is simply 32768 + 4096 +512 +64 +8 +1. There are 8 bits in a byte so anyone who does anything with computers knows these numbers without doing any calculation. Even if you don't, simply directly working it out by multiplication is immensely simpler than what I just watched.
For something this short, just start at the right, times each number by 8 as you go down, then sum (conversely double double double then sum total). Took me about 10s.
00001
00008
00064
00512
04096
32768
=
37449
Sorry, but your solution doesn't look much simpler than just direct calculation.
Or the solution I expected via: (8^7 - 1) / (8 - 1)
Given it's 111111 in base 8 (no need to remember geometric progression), it seems somewhat simpler to solve this as (8^6 - 1) / 7 = (2^18 - 1) / 7 = 262143 / 7
Or for anyone that uses computers at any reasonable level, you already know that this is simply 32768 + 4096 +512 +64 +8 +1. There are 8 bits in a byte so anyone who does anything with computers knows these numbers without doing any calculation. Even if you don't, simply directly working it out by multiplication is immensely simpler than what I just watched.