a(n) = (2^n/n!) * Product_{k=0..n-1} (4*k + 1).
A004981
a(n) = (2^n/n!) * Product_{k=0..n-1} (4*k + 1).
Terms
- a(0) =1a(1) =2a(2) =10a(3) =60a(4) =390a(5) =2652a(6) =18564a(7) =132600a(8) =961350a(9) =7049900a(10) =52169260a(11) =388898120a(12) =2916735900a(13) =21987701400a(14) =166478310600
External references
- oeis: A004981