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Search: id:A147678
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| A147678 |
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Double, add 0, double, add 1, double, add 2, double, add 3, etc. |
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+0
4
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| 1, 2, 2, 4, 5, 10, 12, 24, 27, 54, 58, 116, 121, 242, 248, 496, 503, 1006, 1014, 2028, 2037, 4074, 4084, 8168, 8179, 16358, 16370, 32740, 32753, 65506, 65520, 131040, 131055, 262110, 262126, 524252, 524269, 1048538, 1048556, 2097112, 2097131
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A147675-A147678 are from a quiz that someone asked me to help them with.
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FORMULA
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a(n)=4*a(n-2)-5*a(n-4)+2*a(n-6). G.f.: -x*(2*x+1)*(2*x^4-2*x^2+1)/((2*x^2-1)*(x-1)^2*(1+x)^2). a(n)=(1+(-1)^n)/2+2*A016116(n)-A105811(n+3)/4-3*(n+1)/4. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 22 2009]
a(n) = 2*a(n-1) - (n mod 2)*(a(n-1) - (n-3)/2). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 22 2009]
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CROSSREFS
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Sequence in context: A135586 A116646 A091188 this_sequence A127712 A032090 A000014
Adjacent sequences: A147675 A147676 A147677 this_sequence A147679 A147680 A147681
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Apr 21 2009
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 22 2009
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