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7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8, 23, 22, 21, 20, 19, 18, 17, 16, 31, 30, 29, 28, 27, 26, 25, 24, 39, 38, 37, 36, 35, 34, 33, 32, 47, 46, 45, 44, 43, 42, 41, 40, 55, 54, 53, 52, 51, 50, 49, 48, 63, 62, 61, 60, 59, 58, 57, 56, 71, 70, 69, 68, 67, 66, 65, 64, 79, 78, 77, 76, 75, 74, 73, 72, 87, 86, 85
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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COMMENTS
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A self-inverse permutation of the natural numbers. - Philippe Deléham, Nov 22 2016
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REFERENCES
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E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982, see p. 60.
J. H. Conway, On Numbers and Games. Academic Press, NY, 1976, pp. 51-53.
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LINKS
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FORMULA
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a(n) = n + (-1)^n + 2(-1)^floor(n/2) + 4(-1)^floor(n/4). - Mitchell Harris, Jan 10 2005
G.f.: (8*x^8-x^7-x^6-x^5-x^4-x^3-x^2-x+7) / ((x-1)^2*(x+1)*(x^2+1)*(x^4+1)). - Colin Barker, Jun 29 2014
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MAPLE
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MATHEMATICA
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CoefficientList[Series[(8 x^8 - x^7 - x^6 - x^5 - x^4 - x^3 - x^2 - x + 7)/((x - 1)^2 (x + 1) (x^2 + 1) (x^4 + 1)), {x, 0, 100}], x] (* Vincenzo Librandi, Jun 30 2014 *)
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PROG
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(PARI) Vec((8*x^8-x^7-x^6-x^5-x^4-x^3-x^2-x+7)/((x-1)^2*(x+1)*(x^2+1)*(x^4+1)) + O(x^100)) \\ Colin Barker, Jun 29 2014
(Python)
def a(n): return n^7
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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