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A076335 Brier numbers: both Riesel and Sierpinski, or odd n such that for all k >= 1 the numbers n*2^k + 1 and n*2^k - 1 are composite. 16
143665583045350793098657, 6992565235279559197457863, 14363883005037201769103461, 17830557039648116519025581 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

These are just the smallest examples known - there may be smaller ones.

143665583045350793098657 computed in 2007 by Michael Filaseta, Carrie Finch, Mark Kozek. See http://www.math.sc.edu/~filaseta/papers/SierpinskiEtCoPapNew.pdf.

There are no Brier numbers below 10^9. [From Arkadiusz Wesolowski, Aug 03 2009]

17830557039648116519025581 computed in 2010 by Arkadiusz Wesolowski. [Arkadiusz Wesolowski, Jan 12 2011]

REFERENCES

Fred Cohen and J. L. Selfridge, Not every number is the sum or difference of two prime powers, Math. Comput. 29 (1975), 79-81.

P. Erdos, On integers of the form 2^k + p and some related problems, Summa Brasil. Math. 2 (1950), 113-123.

LINKS

Chris Caldwell, Riesel Numbers

Chris Caldwell, Sierpinski Numbers

Yves Gallot, A search for some small Brier numbers, 2000.

G. L. Honaker, Jr. and Chris Caldwell, Prime Curios! 6992565235279559197457863

Joe McLean, Brier Numbers [Cached copy]

Carlos Rivera, See here for latest information about progress on this sequence

Carlos Rivera, Problem 29 [From Carlos Rivera (cbrfgm(AT)gmail.com), May 30 2010]

Eric Weisstein's World of Mathematics, Brier Number

CROSSREFS

Cf. A194591, A194600, A194603, A194606, A194607, A194608, A194635, A194636, A194637, A194638, A194639, A076336, A076337, A040081, A040076, A103963, A103964, A038699, A050921, A064699, A052333, A003261.

Cf. A180247 gives the primes.

Sequence in context: A008916 A105299 A094232 * A132185 A003942 A003935

Adjacent sequences:  A076332 A076333 A076334 * A076336 A076337 A076338

KEYWORD

bref,nonn

AUTHOR

Olivier Gerard (olivier.gerard(AT)gmail.com), Nov 07 2002

EXTENSIONS

Many terms reported in the Problem 29 from "The Prime Problems & Puzzles Connection" Carlos Rivera (cbrfgm(AT)gmail.com), May 30 2010

Entry revised by Arkadiusz Wesolowski, Jan 12 2011

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Last modified February 16 02:51 EST 2012. Contains 205860 sequences.