a(1) = 1, a(n+1) = a(n)/T(n+1), if T(n+1) divides a(n), else a(n+1) = a(n) *T(n+1), where T(n) = n*(n+1)/2 is a triangular number (A000217).
A111465
a(1) = 1, a(n+1) = a(n)/T(n+1), if T(n+1) divides a(n), else a(n+1) = a(n) *T(n+1), where T(n) = n*(n+1)/2 is a triangular number (A000217).
Terms
- a(0) =1a(1) =3a(2) =18a(3) =180a(4) =12a(5) =252a(6) =9a(7) =324a(8) =14580a(9) =801900a(10) =12150a(11) =947700a(12) =86240700a(13) =821340a(14) =98560800a(15) =13404268800a(16) =87609600a(17) =14981241600a(18) =78848640a(19) =16558214400a(23) =11687339664
External references
- oeis: A111465