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.

A358994 The sum of the numbers that are inside the contour of an n-story Christmas tree drawn at the top of the numerical pyramid containing the positive integers in natural order.

Table of values

n a(n)
1 21
2 151
3 561
4 1503
5 3310
6 6396
7 11256
8 18466
9 28683
10 42645
11 61171
12 85161
13 115596
14 153538
15 200130
16 256596
17 324241
18 404451
19 498693
20 608515
21 735546
22 881496
23 1048156
24 1237398
25 1451175
26 1691521
27 1960551
28 2260461
29 2593528
30 2962110
31 3368646
32 3815656
33 4305741
34 4841583
35 5425945

List of values

[21, 151, 561, 1503, 3310, 6396, 11256, 18466, 28683, 42645, 61171, 85161, 115596, 153538, 200130, 256596, 324241, 404451, 498693, 608515, 735546, 881496, 1048156, 1237398, 1451175, 1691521, 1960551, 2260461, 2593528, 2962110, 3368646, 3815656, 4305741, 4841583, 5425945]