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.

A007595 a(n) = C_n / 2 if n is even or ( C_n + C_((n-1)/2) ) / 2 if n is odd, where C = Catalan numbers (A000108).

Table of values

n a(n)
1 1
2 1
3 3
4 7
5 22
6 66
7 217
8 715
9 2438
10 8398
11 29414
12 104006
13 371516
14 1337220
15 4847637
16 17678835
17 64823110
18 238819350
19 883634026
20 3282060210
21 12233141908
22 45741281820
23 171529836218
24 644952073662
25 2430973304732
26 9183676536076
27 34766775829452
28 131873975875180

List of values

[1, 1, 3, 7, 22, 66, 217, 715, 2438, 8398, 29414, 104006, 371516, 1337220, 4847637, 17678835, 64823110, 238819350, 883634026, 3282060210, 12233141908, 45741281820, 171529836218, 644952073662, 2430973304732, 9183676536076, 34766775829452, 131873975875180]