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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.

A330148 a(n) = Sum_{k=1..n} binomial(n,k) * phi(k) * phi(n - k + 1), where phi = A000010.

Table of values

n a(n)
1 1
2 3
3 11
4 30
5 94
6 238
7 692
8 1596
9 4536
10 9350
11 27840
12 52884
13 149668
14 294838
15 782432
16 1463224
17 4095792
18 7460274
19 20229356
20 36847380
21 100317284
22 170262974
23 492659240
24 814679680
25 2184447760
26 3965791284
27 9988168320
28 17883230712
29 49362800340
30 80674575956
31 213420581248

List of values

[1, 3, 11, 30, 94, 238, 692, 1596, 4536, 9350, 27840, 52884, 149668, 294838, 782432, 1463224, 4095792, 7460274, 20229356, 36847380, 100317284, 170262974, 492659240, 814679680, 2184447760, 3965791284, 9988168320, 17883230712, 49362800340, 80674575956, 213420581248]

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

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