A351768
a(n) = n! * Sum_{k=0..n} k^(n-k) * (n-k)^k/k!.
Original entry on oeis.org
1, 0, 2, 18, 276, 6260, 190950, 7523082, 371286440, 22356290952, 1608686057610, 136069954606190, 13345029902628732, 1500054487474871484, 191349476316804534638, 27464505325501082617170, 4402551348139824475260240, 783025812197886669354545552
Offset: 0
-
Join[{1}, Table[n!*Sum[k^(n-k) * (n-k)^k/k!, {k, 0, n}], {n, 1, 20}]] (* Vaclav Kotesovec, Feb 19 2022 *)
-
a(n) = n!*sum(k=0, n, k^(n-k)*(n-k)^k/k!);
A351779
a(n) = n! * Sum_{k=0..n} (-n)^(n-k) * (n-k)^k/k!.
Original entry on oeis.org
1, -1, 4, -63, 2288, -138525, 12381084, -1528482823, 249005711296, -51739455340953, 13353206066063900, -4190486732316600771, 1571373340568392914288, -693899460077821703051125, 356404409990391961980227068, -210670220153918100996704166975
Offset: 0
A351796
a(n) = n! * Sum_{k=0..n} (-k * (n-k))^k/k!.
Original entry on oeis.org
1, 1, 0, 6, 36, -1240, 36810, -743568, -4441640, 2126086272, -201265464330, 13670088101120, -512174277963612, -50655591400627200, 16935777106057251442, -2936123018591228282880, 368896773292405165345200, -22278163772113766968557568
Offset: 0
-
a[n_] := n!*(1 + Sum[(-k*(n - k))^k/k!, {k, 1, n}]); Array[a, 18, 0] (* Amiram Eldar, Feb 19 2022 *)
-
a(n) = n!*sum(k=0, n, (-k*(n-k))^k/k!);
Showing 1-3 of 3 results.