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Search: id:A061242
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| A061242 |
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Primes of the form 9n - 1. |
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+0
9
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| 17, 53, 71, 89, 107, 179, 197, 233, 251, 269, 359, 431, 449, 467, 503, 521, 557, 593, 647, 683, 701, 719, 773, 809, 827, 863, 881, 953, 971, 1061, 1097, 1151, 1187, 1223, 1259, 1277, 1367, 1439, 1493, 1511, 1583, 1601, 1619, 1637, 1709, 1871, 1889, 1907
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Or, primes of the form 18i-1. Corresponding values of i are in A138918. - Zak Seidov (zakseidov(AT)yahoo.com), Apr 03 2008
A010888(a(n)) = 8. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 25 2005
Contribution from Doug Bell (bell.doug(AT)gmail.com), Mar 23 2009: (Start)
Where a(n) = 9x-1, the integer formed by the repeating digits in the decimal fraction x/a(n) is the smallest integer such that rotating the digits to the left produces a number which is ((x+1)/x) times larger.
Example: x=2, a(n) = 17: 2/17 = 0.1176470588235294... repeating with a cycle of 16.
1176470588235294 x (3/2) = 1764705882352941, which is 1176470588235294 rotated to the left.
The values of x are the only values where rotating an integer one to the left produces a value (x+1)/x times as large. (End)
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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MATHEMATICA
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Select[ Range[ 2500 ], PrimeQ[ # ] && Mod[ #, 9 ] == 8 & ]
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PROGRAM
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(PARI) { n=0; for (i=1, 3279, if (isprime(18*i - 1), write("b061242.txt", n++, " ", 18*i - 1)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 20 2009]
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CROSSREFS
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Cf. A061237-A061241, A138918.
Sequence in context: A042295 A041564 A062342 this_sequence A062343 A044119 A044500
Adjacent sequences: A061239 A061240 A061241 this_sequence A061243 A061244 A061245
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 23 2001
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), May 10 2001
Edited by N. J. A. Sloane (njas(AT)research.att.com) at the suggestion of R. J. Mathar, Apr 30 2008
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