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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.

A204272 a(n) = sigma_2(n)*Pell(n), where sigma_2(n) = A001157(n), the sum of squares of divisors of n.

Table of values

n a(n)
1 1
2 10
3 50
4 252
5 754
6 3500
7 8450
8 34680
9 89635
10 309140
11 700402
12 2910600
13 5688370
14 20195500
15 50706500
16 160553712
17 329639810
18 1248615550
19 2398289458
20 8732957688
21 19306982500
22 56865638380
23 119281100930
24 461838762000
25 853941516771

List of values

[1, 10, 50, 252, 754, 3500, 8450, 34680, 89635, 309140, 700402, 2910600, 5688370, 20195500, 50706500, 160553712, 329639810, 1248615550, 2398289458, 8732957688, 19306982500, 56865638380, 119281100930, 461838762000, 853941516771]

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

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