{"schema":"vela.problem-packet.v0.1","problem":497,"statement":"How many antichains in $[n]$ are there? That is, how many families of subsets of $[n]$ are there such that, if $\\mathcal{F}$ is such a family and $A,B\\in \\mathcal{F}$, then $A\\not\\subseteq B$?","status":"solved","seam":"raw","closureRoutes":[],"obligations":[],"attestations":[],"attempts":[],"velaLean":[],"oeis":[{"id":"A000372","name":"Dedekind numbers or Dedekind's problem: number of monotone Boolean functions of n variables, number of antichains of subsets of an n-set, number of elements in a free distributive lattice on n generat","terms":"2,3,6,20,168,7581,7828354,2414682040998,56130437228687557907788,286386577668298411128469151667598498812366","url":"https://oeis.org/A000372"}],"generated_note":"derived view; the signed event log is the source of truth (vela check / vela reproduce)"}