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A156605
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a(n) = (4^n + 20)/3.
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2
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7, 8, 12, 28, 92, 348, 1372, 5468, 21852, 87388, 349532, 1398108, 5592412, 22369628, 89478492, 357913948, 1431655772, 5726623068, 22906492252, 91625968988, 366503875932, 1466015503708, 5864062014812, 23456248059228, 93824992236892, 375299968947548
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..1000
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FORMULA
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a(n) = -A156591(2n+1).
a(n) = 4 + A154879(2n) = 7 + A002450(n).
a(n) = 4*a(n-1) - 20, n > 0.
G.f.: (7 - 27*x)/((1-x)*(1-4*x)). - R. J. Mathar, Feb 23 2009
E.g.f.: (1/3)*(20*exp(x) + exp(4*x)). - G. C. Greubel, Jun 25 2021
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MATHEMATICA
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(4^Range[0, 40] + 20)/3 (* G. C. Greubel, Jun 25 2021 *)
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PROG
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(MAGMA) [(4^n+20)/3: n in [0..35]]; // Vincenzo Librandi, Jul 24 2011
(Sage) [(4^n + 20)/3 for n in (0..40)] # G. C. Greubel, Jun 25 2021
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CROSSREFS
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Cf. A002450, A154879, A156591.
Sequence in context: A105832 A059177 A065729 * A343298 A061905 A308887
Adjacent sequences: A156602 A156603 A156604 * A156606 A156607 A156608
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KEYWORD
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nonn,easy
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AUTHOR
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Paul Curtz, Feb 11 2009
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EXTENSIONS
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Edited and extended by R. J. Mathar, Feb 23 2009
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STATUS
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approved
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