|
|
A349270
|
|
a(n) = Sum_{k=0..n} (n - k)! * k! / floor(k / 2)!^2, row sums of A349269.
|
|
2
|
|
|
1, 2, 5, 16, 46, 204, 986, 6400, 48094, 420140, 4112822, 44575584, 528787260, 6811260792, 94637153172, 1410542965248, 22446384533142, 379801729831500, 6808478318116238, 128895044005636960, 2569653423591937156, 53808349548318974312, 1180737041228428129580
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
MATHEMATICA
|
Table[Sum[(n-k)! k! / Floor[k/2]!^2, {k, 0, n}], {n, 0, 22}] (* Stefano Spezia, Nov 13 2021 *)
|
|
PROG
|
(PARI) a(n) = sum(k=0, n, (n - k)!*k!/(k\2)!^2); \\ Michel Marcus, Nov 13 2021
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|