We are the UK’s intelligence and cyber agency. Our mission is to help keep the country safe.
Varied and rewarding careers in an environment where people can thrive
Explore our locations across the UK
Over 100 years at the heart of the nation's security
2, 4, 8, 1, 3, 6, 18, 26, ?, 12, 24, 49, 89, 134, 378, 656, 117, 224, 548, 1456, 2912, 4934, 8868, 1771, 3543, ...
-101250000, -1728000, -4900, 360, 675, 200, ?, ...
321, 444, 675, 680, 370, 268, 949, 206, 851, ?, ...
In the original puzzle, again now not working since we changed websites, the answers to these questions could be combined to make an IP address.
This link will take you to where it went:
Continue to Director GCHQ's 2015 Christmas Puzzle - Part 5
Solutions to the GCHQ Director's Christmas Puzzle 2015
Work your way through previous GCHQ Christmas Challenges and see if you can complete them all
Our in-house puzzlers have masterminded seven fiendish brainteasers