cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A069515 Number of transpositions (interchanges of adjacent digits, sometimes called inversions) needed to change all n-digit base 3 numbers into nondecreasing order.

Table of values

n a(n)
1 0
2 3
3 24
4 135
5 648
6 2835
7 11664
8 45927
9 174960
10 649539
11 2361960
12 8444007
13 29760696
14 103630995
15 357128352
16 1219657095
17 4132485216
18 13904090883
19 46490458680
20 154580775111
21 511395045480
22 1684116865683
23 5523066491184

List of values

[0, 3, 24, 135, 648, 2835, 11664, 45927, 174960, 649539, 2361960, 8444007, 29760696, 103630995, 357128352, 1219657095, 4132485216, 13904090883, 46490458680, 154580775111, 511395045480, 1684116865683, 5523066491184]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.