a(n) = (4*n+5)(!^4)/5(!^4), related to A007696(n+1) ((4*n+1)(!^4) quartic, or 4-factorials).
A051617
a(n) = (4*n+5)(!^4)/5(!^4), related to A007696(n+1) ((4*n+1)(!^4) quartic, or 4-factorials).
Terms
- a(0) =1a(1) =9a(2) =117a(3) =1989a(4) =41769a(5) =1044225a(6) =30282525a(7) =999323325a(8) =36974963025
External references
- oeis: A051617