Permutations, combinations, derangements, Stirling and Bell numbers, multinomials and exact big-integer factorials — computed live in your browser. Full Python library with benchmarks in the repo.
Ordered arrangements of r items from n.
Poker hands from a 52-card deck: C(52,5).
Exact big-integer factorial.
Permutations where nothing stays in place (hat-check problem → 1/e).
Signed: coefficients of the falling factorial. Unsigned: permutations of n with exactly k cycles.
Ways to partition n labelled objects into k non-empty unlabelled subsets.
Total partitions of n labelled objects: the row sum of S(n,k).
n! / (g₁!·g₂!·…) where n is the sum of the group sizes.
Stored only in this browser (localStorage) — nothing is sent anywhere. Only calculations you run are listed.
Same three series as growth_chart.py (n!, central binomial C(n,⌊n/2⌋), Bell B(n)), recomputed here with BigInt and plotted on a log₁₀ scale for n = 1…30.