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A216844
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4k^2-8k+2 interleaved with 4k^2-4k+2 for k>=0.
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2
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2, 2, -2, 2, 2, 10, 14, 26, 34, 50, 62, 82, 98, 122, 142, 170, 194, 226, 254, 290, 322, 362, 398, 442, 482, 530, 574, 626, 674, 730, 782, 842, 898, 962, 1022, 1090, 1154, 1226, 1294, 1370, 1442, 1522, 1598, 1682, 1762, 1850, 1934, 2026, 2114, 2210, 2302, 2402
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listen;
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OFFSET
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0,1
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COMMENTS
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The sequence is present as a family of single interleaved sequence of which there are many which are separated or factored out to give individual sequences. The larger sequence produces two smaller interleaved sequences where one of them has the formulas above and the other interleaved sequence has the formulas (4n^2 + 4n -1) and (4n^2+1). The latter interleaved sequence is A214345.
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LINKS
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FORMULA
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G.f.: 2*(1-x-3*x^2+5*x^3)/((1+x)*(1-x)^3). [Bruno Berselli, Sep 30 2012]
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MATHEMATICA
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Flatten[Table[{4 n^2 - 8 n + 2, 4 n^2 - 4 n + 2}, {n, 0, 25}]] (* Bruno Berselli, Sep 30 2012 *)
LinearRecurrence[{2, 0, -2, 1}, {2, 2, -2, 2}, 60] (* Harvey P. Dale, Jul 18 2020 *)
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PROG
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(Magma) &cat[[4*k^2-8*k+2, 4*k^2-4*k+2]: k in [0..25]]; // Bruno Berselli, Sep 30 2012
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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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EXTENSIONS
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STATUS
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approved
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