login
A359435
a(n) = binomial(2*n-1,n) - n^2 - 1.
2
0, 18, 100, 425, 1666, 6370, 24228, 92277, 352594, 1351933, 5200130, 20058103, 77558534, 300539938, 1166802820, 4537567325, 17672631538, 68923264009, 269128936778, 1052049481375, 4116715363270, 16123801840973, 63205303218250, 247959266473375, 973469712823326
OFFSET
3,2
COMMENTS
a(n) is the number of ways to place n indistinguishable balls into n distinguishable boxes with at least 2 boxes remaining empty and not all balls placed in one box.
MATHEMATICA
Table[Binomial[2*n - 1, n] - n^2 - 1, {n, 3, 30}] (* Wesley Ivan Hurt, Jan 20 2024 *)
CROSSREFS
Cf. A352027.
Sequence in context: A259231 A376877 A064604 * A301542 A231138 A140198
KEYWORD
nonn,easy
AUTHOR
Enrique Navarrete, Dec 31 2022
STATUS
approved