Let K be a local ring with a principal maximal ideal J of nilpotent degree 4 with |K/J|>2; a(n) = number of D-invariant ideals in the ring R_n(K,J).

A221704

Let K be a local ring with a principal maximal ideal J of nilpotent degree 4 with |K/J|>2; a(n) = number of D-invariant ideals in the ring R_n(K,J).

Terms

    a(0) =20a(1) =96a(2) =440a(3) =1956a(4) =8522a(5) =36616a(6) =155748a(7) =657468a(8) =2759040a(9) =11523584a(10) =47944480a(11) =198834824a(12) =822365998a(13) =3393330152a(14) =13973673788a(15) =57441828332a(16) =235759507928a(17) =966292212992

External references