OFFSET
0,3
COMMENTS
Equivalently, these are operations for which the functions induced by right multiplication commute with one another. The operations of subtraction, division, and exponentiation satisfy this identity on appropriate domains.
LINKS
J. Benaloh and M. de Mare, One-Way Accumulators: A Decentralized Alternative to Digital Signatures, in: Tor Helleseth, Advances in Cryptology — EUROCRYPT '93, Springer-Verlag Berlin Heidelberg, 1994, 274-285 (Link to PDF).
FORMULA
a(n) = Sum_{k=1..n} k!*Stirling2(n,k)*c(n,k), where c(n,k) is the number of sets of k distinct functions from {1..n} to itself that are mutually commutative.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
David Radcliffe, Dec 21 2018
STATUS
approved