a(n) = n! * Sum_{k=0..floor(n/4)} (-1)^k / (4*k)!.
A349087
a(n) = n! * Sum_{k=0..floor(n/4)} (-1)^k / (4*k)!.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =23a(5) =115a(6) =690a(7) =4830a(8) =38641a(9) =347769a(10) =3477690a(11) =38254590a(12) =459055079a(13) =5967716027a(14) =83548024378
External references
- oeis: A349087