In combinatorics, the nth Bell number, named after Eric Temple Bell, is the number of partitions of a set with n members, or equivalently, the number of equivalence relations on it. Starting with B0 = B1 = 1, the first few Bell numbers are:
- 1, 1, 2, 5, 15, 52, 203, 877, 4140, 21147, 115975, … (sequence A000110 in OEIS).
(See also breakdown by number of subsets/equivalence classes.)
Read more about Bell Number: Partitions of A Set, Properties of Bell Numbers, Asymptotic Limit and Bounds, Triangle Scheme For Calculating Bell Numbers, Prime Bell Numbers
Famous quotes containing the words bell and/or number:
“You owe me ten shillings,
Say the bells of St. Helen’s.
When will you pay me?
Say the bells of Old Bailey.
When I grow rich,
Say the bells of Shoreditch.
Pray when will that be?
Say the bells of Stepney.
I am sure I don’t know,
Says the great bell of Bow.”
—Unknown. The Bells of London (l. 13–22)
“Black lady,
what will I do
without your two flowers?
I have inhabited you, number by number.
I have pushed you in and out like a needle.”
—Anne Sexton (1928–1974)