Bell Number Calculator

Enter a number to instantly calculate its Bell number value.

Calculate the Bell Number Bn = ?

Result

What Is a Bell Number?

In combinatorics, a Bell number represents the total number of ways to partition a set of \( n \) elements into non-empty subsets. Denoted as \( B(n) \), Bell numbers play a crucial role in combinatorics and number theory.

How to Calculate Bell Numbers?

Bell numbers can be calculated recursively or directly using the following relationships: \( B(0) = 1 \) Recursive Formula (for \( n \geq 1 \)): \( B(n) = \sum_{k=0}^{n-1} \binom{n-1}{k} B(k) \) Here, \( \binom{n-1}{k} \) represents the binomial coefficient.

Examples

Example 1: What is the Bell number \( B(8) \)?

Solution:

Calculate \( B(8) \)

\( B(8) = 877 \)

Example 2: How many ways can a set of 10 elements be partitioned into subsets?

Solution:

Calculate \( B(10) \)

\( B(10) = 115975 \)

There are 115975 ways in total.

First 30 Bell Numbers

  • B(0) = 1
  • B(1) = 1
  • B(2) = 2
  • B(3) = 5
  • B(4) = 15
  • B(5) = 52
  • B(6) = 203
  • B(7) = 877
  • B(8) = 4140
  • B(9) = 21147
  • B(10) = 115975
  • B(11) = 678570
  • B(12) = 4213597
  • B(13) = 27644437
  • B(14) = 190899322
  • B(15) = 1382958545
  • B(16) = 10480142147
  • B(17) = 82864869804
  • B(18) = 682076806159
  • B(19) = 5832742205057
  • B(20) = 51724158235372
  • B(21) = 474869816156751
  • B(22) = 4506715738447323
  • B(23) = 44152005855084346
  • B(24) = 445958869294805289
  • B(25) = 4638590332229999353
  • B(26) = 49631246523618756274
  • B(27) = 545717047936059989389
  • B(28) = 6160539404599934652455
  • B(29) = 71339801938860275191172