The unsolved math problem inspired by a children's game

While observing his child play with toy blocks, C. Dudley Langford invented a puzzle that is still unsolved to this day! Special thanks this month to: Daniel Lewis, Kyle, Lee Redden, Mike Robertson. Thanks to all supporters on Patreon!   / mindyourdecisions  

0:00 Problems
3:21 Answers
6:29 Impossible
10:17 Necessary
14:24 Sufficient
18:13 Unsolved

Painting in preview
https://en.wikipedia.org/wiki/Toy_blo...
Interview question
https://math.stackexchange.com/questi...
Susam Pal blog post
https://susam.net/blog/langford-pairi...
Vamshi Jandhyala post
https://vamshij.com/blog/linear-optim...
DataGenetics post
http://datagenetics.com/blog/october3...
Yurii Lahodiuk post
http://lagodiuk.github.io/computer_sc...
Guardian Alex Bellos
https://www.theguardian.com/science/2...
Langford pairing
https://en.wikipedia.org/wiki/Langfor...
OEIS Number of solutions
https://oeis.org/A014552
Counting Skolem-Langford sequences
https://arxiv.org/abs/1507.00315

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