A173488 Partial sums of A055512.

1, 2, 4, 10, 46, 426, 6816, 164778, 5561666, 248740730, 14187451940, 1002045820690, 85615117761142, 8682866612715706, 1029036311254555560, 140656568448867136650, 21929110364021381812410, 3862525357012048643891882, 762298016068721625860646524

Offset

0,2

Comments

Partial sums of the number of lattices with n labeled elements. After a(0) = 1, always even, hence the only prime in the partial sum is 2. The subsequence of semiprimes begins 4, 10, 46.

Links

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

Formula

a(n) = Sum_{i=0..n} A055512(i).

Mathematica

Cases[Import["https://oeis.org/A055512/b055512.txt", "Table"], {_, _}][[All, 2]] // Accumulate (* Jean-François Alcover, Jan 02 2020 *)

Crossrefs

Cf. A055512, A006966, A001035, Main diagonal of A058159.

Sequence in context: A344790 A028404 A113208 * A000613 A322294 A053500

Adjacent sequences: A173485 A173486 A173487 * A173489 A173490 A173491

Keyword

nonn,hard,more

Author

Jonathan Vos Post, Feb 19 2010

Extensions

a(17)-a(18) from Jean-François Alcover, Jan 02 2020

Status

approved