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A048497
a(n) = 2^(n-1)*(4*n - 6) + 4.
1
1, 2, 8, 28, 84, 228, 580, 1412, 3332, 7684, 17412, 38916, 86020, 188420, 409604, 884740, 1900548, 4063236, 8650756, 18350084, 38797316, 81788932, 171966468, 360710148, 754974724, 1577058308, 3288334340, 6845104132
OFFSET
0,2
COMMENTS
Equals binomial transform of A016813 preceded by a "1": (1, 1, 5, 9, 13, 21, ...). [Gary W. Adamson, Jan 13 2009]
FORMULA
From Colin Barker, Oct 07 2012: (Start)
a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3).
G.f.: (1 - 3*x + 6*x^2)/((1-x)*(1-2*x)^2). (End)
MATHEMATICA
LinearRecurrence[{5, -8, 4}, {1, 2, 8}, 30] (* Harvey P. Dale, Apr 16 2019 *)
PROG
(Magma) [2^(n-1)*(4*n-6)+4: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011
CROSSREFS
a(n) = T(3, n), array T given by A048494.
Cf. A016813. [Gary W. Adamson, Jan 13 2009]
Sequence in context: A229935 A082107 A135263 * A118047 A087431 A176758
KEYWORD
nonn,easy
EXTENSIONS
Formula from Ralf Stephan, Jan 15 2004
STATUS
approved