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.

A290485 The largest 3-Carmichael number that is divisible by the n-th odd prime.

Original entry on oeis.org

561, 10585, 52633, 561, 530881, 7207201, 1024651, 1615681, 5444489, 471905281, 36765901, 2489462641, 564651361, 958762729, 17316001, 178837201, 1574601601, 7991602081, 597717121, 962442001, 4461725581, 167385219121, 43286923681, 4523928001, 5755495201
Offset: 1

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Author

Amiram Eldar, Aug 03 2017

Keywords

Comments

Beeger proved in 1950 that if p < q < r are primes such that p*q*r is a Carmichael number, then q < 2p^2 and r < p^3. Therefore there is a finite number of 3-Carmichael numbers which divisible by a given prime.
The terms were calculated using Pinch's tables of Carmichael numbers (see link below).

References

  • N. G. W. H. Beeger, "On composite numbers n for which a^n == 1 (mod n) for every a prime to n", Scripta Mathematica, Vol. 16 (1950), pp. 133-135.

Crossrefs

Cf. A065091 (odd primes), A087788 (3-Carmichael numbers), A141706.