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A173399
Partial sums of A000798.
0
1, 2, 6, 35, 390, 7332, 216859, 9752100, 652531454, 63912820877, 9040966693920, 1825887005430112, 521181458071204133, 208402575114740157174, 115825454552169007964634, 88852094573138413500449755, 93499965506283177978710943850, 134231450058844163850300579669696, 261626767193693218968916427480786899
OFFSET
0,2
COMMENTS
Number of different quasi-orders (or topologies, or transitive digraphs) with n labeled elements.
The subsequence of primes in this partial sum begins: 2, 216859.
FORMULA
a(n) = Sum_{i=0..n} A000798(i).
MATHEMATICA
Cases[Import["https://oeis.org/A000798/b000798.txt", "Table"], {_, _}][[All, 2]] // Accumulate (* Jean-François Alcover, Dec 30 2019 *)
CROSSREFS
Cf. A000798, A001035 (labeled posets), A001930 (unlabeled topologies), A000112 (unlabeled posets), A006057.
Sequence in context: A197973 A107868 A334162 * A193190 A247209 A324577
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Feb 17 2010
EXTENSIONS
Missing term 7332 added and extended by Jean-François Alcover, Dec 30 2019
STATUS
approved