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Search: id:A124625
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| A124625 |
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Even numbers sandwiched between 1's. |
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+0
4
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| 1, 0, 1, 2, 1, 4, 1, 6, 1, 8, 1, 10, 1, 12, 1, 14, 1, 16, 1, 18, 1, 20, 1, 22, 1, 24, 1, 26, 1, 28, 1, 30, 1, 32, 1, 34, 1, 36, 1, 38, 1, 40, 1, 42, 1, 44, 1, 46, 1, 48, 1, 50, 1, 52, 1, 54, 1, 56, 1, 58, 1, 60, 1, 62, 1, 64, 1, 66, 1, 68, 1, 70, 1, 72, 1, 74, 1, 76, 1, 78, 1, 80, 1, 82, 1, 84
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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Interleaving of A000012 and A005843.
Created to simplify the definition of A129952.
a(n) = abs(A009531(n-1)).
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FORMULA
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a(n) = 1 for even n, a(n) = n-1 for odd n.
a(2*n) = 1, a(2*n+1) = 2*n.
G.f.: (1-x^2+2*x^3)/((1-x)^2*(1+x)^2).
a(n)=C(n+1,((n+2) mod 2))-1-(-1)^(n+1) - Paolo P. Lava (ppl(AT)spl.at), Aug 29 2007
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PROGRAM
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(PARI) {for(n=0, 85, print1(if(n%2>0, n-1, 1), ", "))}
(MAGMA) &cat[ [ 1, 2*k ]: k in [0..42] ];
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CROSSREFS
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Cf. A000012 (all 1's), A005843 (even numbers), A009531.
Sequence in context: A083258 A083259 A009531 this_sequence A137374 A131516 A088140
Adjacent sequences: A124622 A124623 A124624 this_sequence A124626 A124627 A124628
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jun 13 2007
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EXTENSIONS
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More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 16 2007
Edited by N. J. A. Sloane (njas(AT)research.att.com), May 21 2008 at the suggestion of R. J. Mathar
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