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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.

A166678 a(n) = pi((sqrt(P(n))+1)^2) - pi(P(n)), where pi(n) = number of primes <= n and P(n) = n-th primorial.

Table of values

n a(n)
1 2
2 2
3 3
4 6
5 14
6 34
7 110
8 384
9 1540
10 7019
11 34501
12 183439
13 1045196
14 6164423
15 38285946

List of values

[2, 2, 3, 6, 14, 34, 110, 384, 1540, 7019, 34501, 183439, 1045196, 6164423, 38285946]

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

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