A176527 Partial sums of A006058.

1, 2, 5, 21, 166, 2277, 49901, 1675904, 84239935, 6231045077, 668949067432, 103005162942955, 22511886374045653, 6918461813753405930, 2965189776573865320121, 1759287329824925168339697, 1435531006280642249195752862, 1601571709194974043628781397985, 2430449338115875591262479128994073

Offset: 0

Author

Jonathan Vos Post, Apr 19 2010

Keywords

• nonn

Comments

Partial sums of number of connected labeled topologies with n points. The subsequence of primes in this partial sum begins: 2, 5, and then what?

Crossrefs

Cf. A000798, A006058.

Programs

Mathematica

Cases[Import["https://oeis.org/A006058/b006058.txt", "Table"], {, }][[All, 2]] // Accumulate (* Jean-François Alcover, Jan 01 2020 *)

Formula

a(n) = Sum_{i=0..n} A006058(i) = Sum_{i=0..n} Sum_{k=0..i-1} C(i, k)*A000798(k) (for i>=1).

Extensions

a(16)-a(18) from Jinyuan Wang, Feb 23 2020