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A097062
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Interleave 2*n+1 and 2*n-1.
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6
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1, -1, 3, 1, 5, 3, 7, 5, 9, 7, 11, 9, 13, 11, 15, 13, 17, 15, 19, 17, 21, 19, 23, 21, 25, 23, 27, 25, 29, 27, 31, 29, 33, 31, 35, 33, 37, 35, 39, 37, 41, 39, 43, 41, 45, 43, 47, 45, 49, 47, 51, 49, 53, 51, 55, 53, 57, 55, 59, 57, 61, 59, 63, 61, 65, 63, 67, 65, 69, 67, 71, 69, 73, 71, 75, 73, 77, 75, 79, 77, 81, 79, 83, 81, 85, 83, 87, 85
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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G.f.: (1-2*x+3*x^2)/((1-x^2)*(1-x)).
a(n) = (2*n-1)/2 + 3*(-1)^n/2.
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MATHEMATICA
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LinearRecurrence[{1, 1, -1}, {1, -1, 3}, 100] (* Amiram Eldar, May 21 2021 *)
With[{nn=91}, Riffle[Range[1, nn, 2], Range[-1, nn-2, 2]]] (* Harvey P. Dale, Jan 23 2023 *)
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PROG
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(Haskell)
import Data.List (transpose)
a097062 n = a097062_list !! n
a097062_list = concat $ transpose [a005408_list, (-1) : a005408_list]
(PARI) Vec((1-2*x+3*x^2)/((1-x^2)*(1-x)) + O(x^100)) \\ Altug Alkan, Nov 13 2015
(Magma) [(2*n-1)/2 + 3*(-1)^n/2 : n in [0..100]]; // Wesley Ivan Hurt, May 22 2021
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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