Number of transpositions (interchanges of adjacent digits, sometimes called inversions) needed to change all n-digit base 3 numbers into nondecreasing order.

A069515

Number of transpositions (interchanges of adjacent digits, sometimes called inversions) needed to change all n-digit base 3 numbers into nondecreasing order.

Terms

    a(0) =0a(1) =3a(2) =24a(3) =135a(4) =648a(5) =2835a(6) =11664a(7) =45927a(8) =174960a(9) =649539a(10) =2361960a(11) =8444007a(12) =29760696a(13) =103630995a(14) =357128352a(15) =1219657095a(16) =4132485216a(17) =13904090883a(18) =46490458680a(19) =154580775111a(20) =511395045480

External references