data/problems/419.yml
---
:id: 419
:name: Look and say sequence
:url: https://projecteuler.net/problem=419
:content: "The **look and say** sequence goes 1, 11, 21, 1211, 111221, 312211, 13112221,
1113213211, ... \nThe sequence starts with 1 and all other members are obtained
by describing the previous member in terms of consecutive digits. \nIt helps to
do this out loud: \n1 is 'one one' → 11 \n11 is 'two ones' → 21 \n21 is 'one
two and one one' → 1211 \n1211 is 'one one, one two and two ones' → 111221 \n111221
is 'three ones, two twos and one one' → 312211 \n...\n\nDefine A(n), B(n) and C(n)
as the number of ones, twos and threes in the n'th element of the sequence respectively.
\ \nOne can verify that A(40) = 31254, B(40) = 20259 and C(40) = 11625.\n\nFind
A(n), B(n) and C(n) for n = 10<sup>12</sup>. \n Give your answer modulo 2<sup>30</sup>
and separate your values for A, B and C by a comma. \n E.g. for n = 40 the answer
would be 31254,20259,11625\n\n"