Partition Number Calculator

How many sums equal n?

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About Partition Number Calculator

A partition number calculator computing p(n) via dynamic programming. p(1)=1, p(2)=2, p(3)=3, p(4)=5, p(5)=7. Hardy-Ramanujan asymptotic: p(n) ~ exp(π√(2n/3))/(4n√3). Euler's generating function: Π(1-x^k)^{-1}. Client-side.

Partition Number Calculator Features

  • p(n) value
  • All partitions
  • Hardy-Ramanujan
  • Sequence
  • Distinct parts
Partition numbers p(n): ways to write n as unordered sums. p(4)=5: 4, 3+1, 2+2, 2+1+1, 1+1+1+1. Generating function: Σp(n)x^n = Π_{k≥1}1/(1-x^k). Hardy-Ramanujan: p(n)~exp(π√(2n/3))/(4n√3). Ramanujan congruences: p(5n+4)≡0 mod 5.

How to Use

Enter n:

  • p(n): Total partitions
  • List: All partitions
  • Distinct: Parts all different

Ramanujan

Remarkable congruences: p(5n+4)≡0(mod 5), p(7n+5)≡0(mod 7), p(11n+6)≡0(mod 11). The Hardy-Ramanujan-Rademacher formula gives an EXACT series for p(n), one of the most beautiful results in analytic number theory.

Applications

  • Statistical mechanics (Bose-Einstein)
  • Representation theory (symmetric group)
  • Algebraic geometry (Hilbert schemes)
  • Combinatorics (q-series)

Step-by-Step Instructions

  1. 1Enter n.
  2. 2Compute p(n).
  3. 3List partitions.
  4. 4Check Hardy-Ramanujan.
  5. 5See distinct.

Partition Number Calculator — Frequently Asked Questions

How fast do partition numbers grow?+

Superexponentially! p(100)=190,569,292,356. The Hardy-Ramanujan asymptotic p(n)~exp(π√(2n/3))/(4n√3) shows partition numbers grow like exp(C√n). This is between polynomial and exponential growth.

What are Ramanujan's congruences?+

p(5n+4)≡0(mod 5), p(7n+5)≡0(mod 7), p(11n+6)≡0(mod 11). Ramanujan discovered these in 1919. Much deeper congruences exist for prime powers. These connect partitions to modular forms.

What's the difference from compositions?+

Partitions are UNORDERED: 2+1 = 1+2. Compositions are ORDERED: 2+1 ≠ 1+2. So compositions of n number 2^{n-1}, far more than p(n). Partitions have richer structure and deeper theory.

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