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A029749
Numbers of the form 2^k times 1, 5 or 7.
1
1, 2, 4, 5, 7, 8, 10, 14, 16, 20, 28, 32, 40, 56, 64, 80, 112, 128, 160, 224, 256, 320, 448, 512, 640, 896, 1024, 1280, 1792, 2048, 2560, 3584, 4096, 5120, 7168, 8192, 10240, 14336, 16384, 20480, 28672, 32768, 40960, 57344, 65536, 81920, 114688, 131072
OFFSET
0,2
FORMULA
From Colin Barker, Jul 19 2013: (Start)
a(n) = 2*a(n-3) for n>4.
G.f.: -(3*x^4 + 3*x^3 + 4*x^2 + 2*x + 1) / (2*x^3 - 1). (End)
Sum_{n>=0} 1/a(n) = 94/35. - Amiram Eldar, Jan 21 2022
MATHEMATICA
CoefficientList[Series[-(3 x^4 + 3 x^3 + 4 x^2 + 2 x + 1) / (2 x^3 - 1), {x, 0, 40}], x] (* Vincenzo Librandi, Jul 20 2013 *)
CROSSREFS
KEYWORD
nonn,easy
EXTENSIONS
More terms from Colin Barker, Jul 19 2013
STATUS
approved