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.

A000316 Two decks each have n kinds of cards, 2 of each kind. The first deck is laid out in order. The second deck is shuffled and laid out next to the first. A match occurs if a card from the second deck is next to a card of the same kind from the first deck. a(n) is the number of ways of achieving no matches.

Table of values

n a(n)
0 1
1 0
2 4
3 80
4 4752
5 440192
6 59245120
7 10930514688
8 2649865335040
9 817154768973824
10 312426715251262464
11 145060238642780180480
12 80403174342119992692736
13 52443098500204184915312640
14 39764049487996490505336537088

List of values

[1, 0, 4, 80, 4752, 440192, 59245120, 10930514688, 2649865335040, 817154768973824, 312426715251262464, 145060238642780180480, 80403174342119992692736, 52443098500204184915312640, 39764049487996490505336537088]

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

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