|
|
A279881
|
|
a(n) = A168467(n) * Sum_{k=0..n}(2^k*(k!)^2 / (2*k+1)!).
|
|
1
|
|
|
1, 8, 1056, 5529600, 2040024268800, 82038030902231040000, 512596445591262883479552000000, 671373457257855830831011844849664000000000, 238977230623673235057124486022413812190150656000000000000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(0) = 1, a(n) = a(n-1) * (2*n + 1)! + 2^n * (n!)^2 * A168467(n-1).
|
|
MATHEMATICA
|
Table[Product[((2 k + 2) (2 k + 3))^(n - k), {k, 0, n}] Sum[(2^j*(j!)^2/(2 j + 1)!), {j, 0, n}], {n, 0, 8}] (* Michael De Vlieger, Dec 22 2016 *)
|
|
PROG
|
(PARI) a(n) = prod(k=1, n, (2*k+1)!) * sum(k=0, n, 2^k * (k!)^2 / (2*k+1)!)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|