A173399 Partial sums of A000798.

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.

Links

Table of n, a(n) for n=0..18.

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

Adjacent sequences: A173396 A173397 A173398 * A173400 A173401 A173402

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