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A006285
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Odd numbers not of form p + 2^x (de Polignac numbers).
(Formerly M5390)
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7
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1, 127, 149, 251, 331, 337, 373, 509, 599, 701, 757, 809, 877, 905, 907, 959, 977, 997, 1019, 1087, 1199, 1207, 1211, 1243, 1259, 1271, 1477, 1529, 1541, 1549, 1589, 1597, 1619, 1649, 1657, 1719, 1759, 1777, 1783, 1807, 1829, 1859, 1867, 1927, 1969, 1973
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Contains both primes (A065381) and composites (A098237). - Jonathan Vos Post (jvospost3(AT)gmail.com), Jun 19 2008
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REFERENCES
| N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
D. Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, see #127.
Clifford A. Pickover, A Passion for Mathematics, John Wiley & Sons, Inc., NJ, 2005, pp. 62 & 300
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LINKS
| T. D. Noe, Table of n, a(n) for n = 1..10000
P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 193, ex. 5.1.6, p. 216ff. [?Broken link]
P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 193, ex. 5.1.6, p. 216ff.
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MATHEMATICA
| Do[ i = 0; l = Ceiling[ N[ Log[ 2, n ] ] ]; While[ ! PrimeQ[ n - 2^i ] && i < l, i++ ]; If[ i == l, Print[ n ] ], {n, 1, 2000, 2} ]
Join[{1}, Select[Range[5, 1999, 2], !MemberQ[PrimeQ[#-2^Range[Floor[ Log[ 2, #]]]], True]&]] (* From Harvey P. Dale, Jul 22 2011 *)
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PROG
| (PARI) isA006285(n, i=1)={ n%2 & until( isprime(n-i) | n<i<<=1, ); i>n } \\ - M. F. Hasler (www.univ-ag.fr/~mhasler), Jun 19 2008
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CROSSREFS
| Cf. A133122, A098237, A065381, A156695.
Sequence in context: A126096 A164966 A178088 * A094933 A156702 A180536
Adjacent sequences: A006282 A006283 A006284 * A006286 A006287 A006288
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KEYWORD
| nonn,nice,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from Larry Reeves (larryr(AT)acm.org), Apr 13 2000
Link to Pollack Notes corrected by Rainer Rosenthal (r.rosenthal(AT)web.de), Feb 03 2009
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