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1, 27, 105, 235, 417, 651, 937, 1275, 1665, 2107, 2601, 3147, 3745, 4395, 5097, 5851, 6657, 7515, 8425, 9387, 10401, 11467, 12585, 13755, 14977, 16251, 17577, 18955, 20385, 21867, 23401, 24987, 26625, 28315, 30057, 31851, 33697, 35595, 37545
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| The identity (26*n^2+1)^2-(169*n^2+13)*(2*n)^2 = 1 can be written as a(n)^2 - A158548(n)*A005843(n)^2 = 1.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
| G.f.: (1+24*x+27*x^2)/(1-x)^3.
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
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MATHEMATICA
| Table[26n^2+1, {n, 0, 50}] (* From Harvey P. Dale, Feb 21 2011 *)
LinearRecurrence[{3, -3, 1}, {1, 27, 105}, 50] (* Vincenzo Librandi, Feb 14 2012 *)
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PROG
| (MAGMA) I:=[1, 27, 105]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Feb 14 2012
(PARI) for(n=1, 40, print1(26*n^2+1", ")); \\ Vincenzo Librandi, Feb 14 2012
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CROSSREFS
| Cf. A005843, A158548.
Sequence in context: A036346 A140376 A046347 * A044278 A044659 A134171
Adjacent sequences: A158546 A158547 A158548 * A158550 A158551 A158552
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 21 2009
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EXTENSIONS
| Comment rewritten, a(0) added - R. J. Mathar, Oct 16 2009
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