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A113778
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Invert blocks of four in the sequence of natural numbers.
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0
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4, 3, 2, 1, 8, 7, 6, 5, 12, 11, 10, 9, 16, 15, 14, 13, 20, 19, 18, 17, 24, 23, 22, 21, 28, 27, 26, 25, 32, 31, 30, 29, 36, 35, 34, 33, 40, 39, 38, 37
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,0,0,1,-1).
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FORMULA
| a(n)=k*floor((n+k-1)/k)-(n-1) mod k; k=4, n=1, 2, ...
a(n)=n-cos(n*pi)-2*sqrt(2)*cos((2*n+1)*pi/4) [From Jaume Oliver Lafont (joliverlafont(AT)gmail.com), Dec 10 2008]
G.f. x*( 4-x-x^2-x^3+3*x^4 ) / ( (1+x)*(1+x^2)*(x-1)^2 ). - R. J. Mathar, Apr 02 2011
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MATHEMATICA
| With[{k=4}, Table[k Floor[(n+k-1)/k]-Mod[n-1, k], {n, 1, 10k}]]
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CROSSREFS
| Cf. A113655.
Sequence in context: A194750 A051623 A194743 * A155172 A129154 A055115
Adjacent sequences: A113775 A113776 A113777 * A113779 A113780 A113781
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KEYWORD
| nonn
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AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Jan 20 2006
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