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Search: id:A101562
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| A101562 |
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a(n)=(-1)^n*coefficient of x^n in sum{k>=1,x^(k-1)/(1+4x^k)}. |
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+0
3
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| 1, 3, 17, 67, 257, 1011, 4097, 16451, 65553, 261891, 1048577, 4195379, 16777217, 67104771, 268435729, 1073758275, 4294967297, 17179804659, 68719476737, 274878168899, 1099511631889, 4398045462531, 17592186044417, 70368748389427
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=sum{k=0..n, (-1)^(n-k)*if(mod(n+1, k+1)=0, 1, 0)*4^k}
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CROSSREFS
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Cf. A051731, A081295, A048272, A101561, A101563.
Sequence in context: A130857 A120386 A061982 this_sequence A034566 A069468 A128948
Adjacent sequences: A101559 A101560 A101561 this_sequence A101563 A101564 A101565
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Dec 07 2004
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