---
id: 5900f4d51000cf542c50ffe8
challengeType: 5
title: 'Problem 361: Subsequence of Thue-Morse sequence'
---
## Description
The Thue-Morse sequence {Tn} is a binary sequence satisfying:
T0 = 0
T2n = Tn
T2n+1 = 1 - Tn
The first several terms of {Tn} are given as follows:
01101001100101101001011001101001....
We define {An} as the sorted sequence of integers such that the binary expression of each element appears as a subsequence in {Tn}.
For example, the decimal number 18 is expressed as 10010 in binary. 10010 appears in {Tn} (T8 to T12), so 18 is an element of {An}.
The decimal number 14 is expressed as 1110 in binary. 1110 never appears in {Tn}, so 14 is not an element of {An}.
The first several terms of An are given as follows:
n0123456789101112…An012345691011121318…
We can also verify that A100 = 3251 and A1000 = 80852364498.
Find the last 9 digits of .
## Instructions
## Tests
```yml
tests:
- text: euler361() should return 178476944.
testString: assert.strictEqual(euler361(), 178476944, 'euler361() should return 178476944.');
```
## Challenge Seed
```js
function euler361() {
// Good luck!
return true;
}
euler361();
```