login
A195394
a(n) = (10*n)!
1
1, 3628800, 2432902008176640000, 265252859812191058636308480000000, 815915283247897734345611269596115894272000000000, 30414093201713378043612608166064768844377641568960512000000000000
OFFSET
0,2
FORMULA
From Amiram Eldar, Apr 03 2021: (Start)
a(n) = A000142(A008592(n)).
Sum_{n>=0} 1/a(n) = A195070.
Sum_{n>=0} (-1)^n/a(n) = A196498. (End)
MATHEMATICA
a[n_] := (10*n)!; Array[a, 6, 0] (* Amiram Eldar, Apr 03 2021 *)
PROG
(Magma) [Factorial(10*n): n in [0..10]]
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Sep 24 2011
STATUS
approved