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A155816
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First nonzero digit in the decimal expansion of (cos Pi/4)^n.
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1
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7, 5, 3, 2, 1, 1, 8, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 5, 4, 2, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 5, 4, 2, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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(cos Pi/4)^4=0.25, so a(4)=2.
(cos Pi/4)^8=0.0625, so a(8)=6.
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MAPLE
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f:= proc(n) local t, m;
m:= 1 + ilog10(floor(2^(n/2)));
floor(10^m * 2^(-n/2))
end proc:
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MATHEMATICA
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With[{c=Cos[Pi/4]}, Table[First[RealDigits[N[c^n, 20]][[1]]], {n, 120}]] (* Harvey P. Dale, Nov 07 2012 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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Avik Roy (avik_3.1416(AT)yahoo.co.in), Jan 28 2009
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EXTENSIONS
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STATUS
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approved
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