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.

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A083556 n-th Payam number E_{+}(n), defined as the smallest positive odd integer k such that for every positive integer n, the number k*2^n+1 is not divisible by any primes p such that the multiplicative order of 2 mod p is less than or equal to e.

Original entry on oeis.org

3, 9, 15, 105, 105, 105, 105, 105, 165, 165, 75075, 75075, 75075, 75075, 75075, 75075, 855855, 855855, 5583435, 5583435, 5583435, 18625035, 18625035, 18625035, 18625035, 18625035, 27183585, 27183585, 27183585, 27183585, 27183585
Offset: 2

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Author

David Terr, Jun 10 2003

Keywords

Comments

Payam numbers are good candidates for looking for Proth primes, i.e. primes of the form k*2^n+1

Examples

			E_{+}(3) = 9 because 9 is the smallest odd integer k such that for every nonnegative integer n, k*2^n+1 is not divisible by 3 or 7, the only primes p for which the multiplicative order of 2 mod p is less than or equal to 3.
		

Crossrefs

Cf. A080076.
Cf. A083391.
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