The Number That Linked Two Unrelated Fields

196884 comes from complex analysis. It is the first interesting coefficient of the j-invariant, the function that labels the shape of a lattice in the plane — and in this video it is computed from E₄³/Δ rather than looked up, so you can watch it fall out of the definition. CHAPTERS 0:00 The Two Numbers 1:19 Where j Comes From 2:45 The Monster 4:20 McKay Writes It Down 5:36 The Second Coefficient 7:04 What the Pattern Means 8:27 Ogg Got There First 9:47 Borcherds Proves It 11:00 What Is Explained 12:08 It Happened Again Music by Vincent Rubinetti Download the music on Bandcamp: https://vincerubinetti.bandcamp.com/a...