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:
“I was thinking of a son.
The womb is not a clock
nor a bell tolling,
but in the eleventh month of its life
I feel the November
of the body as well as of the calendar.”
—Anne Sexton (1928–1974)
“While I do not suggest that humanity will ever be able to dispense with its martyrs, I cannot avoid the suspicion that with a little more thought and a little less belief their number may be substantially reduced.”
—J.B.S. (John Burdon Sanderson)