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.

A231720 a(0)=1, after which, for any n uniquely written as du*u! + ... + d2*2! + d1*1! (each di in range 0..i), a(n) = (du+1)*(u+1)! + ... + (d2+1)*3! + (d1+1)*2! + 1; the natural numbers with their factorial base representation (A007623) shifted left one step and each digit incremented by one, converted back to decimal.

Table of values

n a(n)
0 1
1 5
2 15
3 17
4 21
5 23
6 57
7 59
8 63
9 65
10 69
11 71
12 81
13 83
14 87
15 89
16 93
17 95
18 105
19 107
20 111
21 113
22 117
23 119
24 273
25 275
26 279
27 281
28 285
29 287
30 297
31 299
32 303
33 305
34 309
35 311
36 321
37 323
38 327
39 329
40 333
41 335
42 345
43 347
44 351
45 353
46 357
47 359
48 393
49 395
50 399
51 401
52 405
53 407
54 417
55 419

List of values

[1, 5, 15, 17, 21, 23, 57, 59, 63, 65, 69, 71, 81, 83, 87, 89, 93, 95, 105, 107, 111, 113, 117, 119, 273, 275, 279, 281, 285, 287, 297, 299, 303, 305, 309, 311, 321, 323, 327, 329, 333, 335, 345, 347, 351, 353, 357, 359, 393, 395, 399, 401, 405, 407, 417, 419]

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

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