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A344260
a(n) is the number of relations from an n-element set into a set of at most n elements.
1
1, 3, 21, 585, 69905, 34636833, 69810262081, 567382630219905, 18519084246547628289, 2422583247133816584929793, 1268889750375080065623288448001, 2659754699919401766201267083003561985, 22306191045953951743035482794815064402563073, 748380193317489370459454048174977015562807531282433
OFFSET
0,2
COMMENTS
Symmetrically, also the number of relations from a set of at most n elements into an n-element set.
FORMULA
a(n) = (2^(n+n^2) - 1)/(2^n - 1) for n > 0 and a(0) = 1.
a(n) ~ 2^(n^2).
a(n) = A275779(n) + 1. - Hugo Pfoertner, May 14 2021
MATHEMATICA
Join[{1}, Table[(2^(n+n^2)-1)/(2^n-1), {n, 13}]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Stefano Spezia, May 13 2021
STATUS
approved