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A125169
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a(n) = 16*n + 15.
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9
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15, 31, 47, 63, 79, 95, 111, 127, 143, 159, 175, 191, 207, 223, 239, 255, 271, 287, 303, 319, 335, 351, 367, 383, 399, 415, 431, 447, 463, 479, 495, 511, 527, 543, 559, 575, 591, 607, 623, 639, 655, 671, 687, 703, 719, 735, 751, 767, 783, 799, 815, 831, 847
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OFFSET
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0,1
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COMMENTS
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The identity (16*n + 15)^2 - (16*(n+1)^2 - 2*(n+1))*4^2 = 1 can be written as a(n)^2 - A158058(n+1)*4^2 = 1. - Vincenzo Librandi, Feb 01 2012
a(n-3), n >= 3, appears in the third column of triangle A239126 related to the Collatz problem. - Wolfdieter Lang, Mar 14 2014
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LINKS
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FORMULA
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a(n) = 2*a(n-1) - a(n-2); a(0)=15, a(1)=31. - Harvey P. Dale, Jan 03 2012
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MATHEMATICA
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Table[16n + 15, {n, 0, 100}]
LinearRecurrence[{2, -1}, {15, 31}, 100] (* or *) Range[15, 1620, 16] (* Harvey P. Dale, Jan 03 2012 *)
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PROG
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(Magma) I:=[15, 31]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..60]]; // Vincenzo Librandi, Jan 04 2012
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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