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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.

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A176268 Primes of a Generalized Cunningham chain of length 9 by the function f(p) = 2 * p + 13.

Original entry on oeis.org

3467, 6947, 13907, 27827, 55667, 111347, 222707, 445427, 890867
Offset: 1

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Author

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 13 2010

Keywords

Comments

See comments and references of A176223 and A176247
Chain of 8 primes: 2, 17, 47, 107, 227, 467, 947, 1907
It is conjectured that arbitrarily long such chains exist

Examples

			3467 = prime(486), (3467 - 13)/ 2 = 1727 = 11 * 157 is composite
f(3467) = 6947 = prime(891), f(6947) = 13907 = prime(1644)
f(13907) = 27827 = prime(3040), f( 27827) = 55667 = prime(5649)
f(55667) = 111347 = prime(10565), f(111347) = 222707 = prime(19832)
f(222707) = 445427 = prime(37374), f(445427) = 890867 = prime(70612)
f(890867) = 1781747 = 11 * 161977
3467 is smallest prime for such a chain of 9 primes

References

  • Joe Buhler: Algorithmic Number Theory: Third International Symposium, ANTS-III, New York: Springer, 1998
  • David J. Darling: The Universal Book of Mathematics: From Abracadabra to Zeno's Paradoxes, Hoboken: John Wiley & Sons, 2004
  • Paulo Ribenboim: Die Welt der Primzahlen. Geheimnisse und Rekorde, Springer-Verlag GmbH & Co. KG, 2006

Crossrefs

A000040, A005602, A005603, A176247
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