A174146 Partial sums of A000238.

1, 2, 5, 13, 40, 131, 481, 1857, 7600, 32235, 141203, 633383, 2899885, 13498337, 63734268, 304606922, 1471339736, 7173341171, 35262128485, 174617051093, 870425605393, 4364815662605, 22006511124267, 111501534635143, 567511427859428, 2900508758069868

Offset

1,2

Comments

Partial sums of number of oriented trees with n nodes. The subsequence of primes in this partial sum begins: 2, 5, 13, 131, 633383, 870425605393, 55532683410408578237, 290078510058531496879, 26098901136734259174974296003.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Formula

a(n) = Sum_{i=1..n} A000238(i).

Example

a(32) = 1 + 1 + 3 + 8 + 27 + 91 + 350 + 1376 + 5743 + 24635 + 108968 + 492180 + 2266502 + 10598452 + 50235931 + 240872654 + 1166732814 + 5702001435 + 28088787314 + 139354922608 + 695808554300 + 3494390057212 + 17641695461662 + 89495023510876 + 456009893224285 + 2332997330210440 + 11980753878699716 + 61739654323377296 + 319188605907760846 + 1655151350788152551 + 8606939469625111036 + 44874783067127406924.

Crossrefs

Cf. A000238.

Sequence in context: A202153 A149864 A149865 * A375677 A149866 A149867

Adjacent sequences: A174143 A174144 A174145 * A174147 A174148 A174149

Keyword

nonn

Author

Jonathan Vos Post, Mar 09 2010

Status

approved