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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.

A256823 Numbers n such that A257378(n)=A257379(n), so the prime numbers k*n*2^n-1 and k*n*2^n+1 are twin primes for the smallest k such that k*n*2^n-1 is a prime number.

Table of values

n a(n)
1 4
2 7
3 9
4 11
5 27
6 40
7 63
8 80
9 120
10 173
11 227
12 358
13 445
14 525
15 767
16 1164
17 2180
18 5368
19 7898

List of values

[4, 7, 9, 11, 27, 40, 63, 80, 120, 173, 227, 358, 445, 525, 767, 1164, 2180, 5368, 7898]

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

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