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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.

A189177 Diagonal sums of the Riordan matrix (1+x/sqrt(1-4*x),(1-sqrt(1-4*x))/2) (A189175).

Table of values

n a(n)
0 1
1 1
2 3
3 8
4 26
5 88
6 311
7 1125
8 4139
9 15411
10 57901
11 219070
12 833509
13 3185834
14 12223298
15 47048989
16 181596815
17 702589992
18 2723964698
19 10580344863
20 41163089721
21 160380285133
22 625698670720
23 2443971874519
24 9556455398766
25 37404704660996
26 146537441530003
27 574556162261917

List of values

[1, 1, 3, 8, 26, 88, 311, 1125, 4139, 15411, 57901, 219070, 833509, 3185834, 12223298, 47048989, 181596815, 702589992, 2723964698, 10580344863, 41163089721, 160380285133, 625698670720, 2443971874519, 9556455398766, 37404704660996, 146537441530003, 574556162261917]

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

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