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.

A074678 a(n) = Sum_{j=0..floor(n/2)} (-1)^(j+floor(n/2))*S(2j+q), where S(n) are generalized tribonacci numbers (A001644) and q = (1-(-1)^n)/2.

Table of values

n a(n)
0 3
1 1
2 0
3 6
4 11
5 15
6 28
7 56
8 103
9 185
10 340
11 630
12 1159
13 2127
14 3912
15 7200
16 13243
17 24353
18 44792
19 82390
20 151539
21 278719
22 512644
23 942904
24 1734271
25 3189817
26 5866988
27 10791078
28 19847887
29 36505951
30 67144912
31 123498752
32 227149619
33 417793281

List of values

[3, 1, 0, 6, 11, 15, 28, 56, 103, 185, 340, 630, 1159, 2127, 3912, 7200, 13243, 24353, 44792, 82390, 151539, 278719, 512644, 942904, 1734271, 3189817, 5866988, 10791078, 19847887, 36505951, 67144912, 123498752, 227149619, 417793281]