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.

A134064 Let P(A) be the power set of an n-element set A. Then a(n) = the number of pairs of elements {x,y} of P(A) for which either 0) x and y are intersecting but for which x is not a subset of y and y is not a subset of x, or 1) x and y are intersecting and for which either x is a proper subset of y or y is a proper subset of x, or 2) x = y.

Table of values

n a(n)
0 1
1 2
2 6
3 23
4 96
5 407
6 1716
7 7163
8 29616
9 121487
10 495276
11 2009603
12 8124936
13 32761367
14 131834436
15 529712843
16 2125993056
17 8525430047
18 34166159196
19 136858084883
20 548012945976
21 2193794127527
22 8780404589556
23 35137304693723
24 140596281975696
25 562526325893807
26 2250528914325516

List of values

[1, 2, 6, 23, 96, 407, 1716, 7163, 29616, 121487, 495276, 2009603, 8124936, 32761367, 131834436, 529712843, 2125993056, 8525430047, 34166159196, 136858084883, 548012945976, 2193794127527, 8780404589556, 35137304693723, 140596281975696, 562526325893807, 2250528914325516]

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

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