a(n) = if n even then a(n - 1) - (n - 1)*a(n - 2) otherwise 2*(a(n - 1) + (n - 1)*a(n - 2)).
A122017
a(n) = if n even then a(n - 1) - (n - 1)*a(n - 2) otherwise 2*(a(n - 1) + (n - 1)*a(n - 2)).
Terms
- a(0) =1a(1) =2a(2) =1a(3) =10a(4) =7a(5) =94a(6) =59a(7) =1246a(8) =833a(9) =21602a(10) =14105a(11) =460250a(12) =305095a(13) =11656190a(14) =7689955a(15) =341753230a(16) =226403905a(17) =11388911170a(18) =7540044785a(19) =425080891690a(20) =281820040775
External references
- oeis: A122017