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A101563
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a(n)=(-1)^n*coefficient of x^n in sum{k>=1,x^(k-1)/(1+10x^k)}.
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3
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1, 9, 101, 1009, 10001, 99909, 1000001, 10001009, 100000101, 999990009, 10000000001, 100000100909, 1000000000001, 9999999000009, 100000000010101, 1000000010001009, 10000000000000001, 99999999900099909
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| a(n)=sum{k=0..n, (-1)^(n-k)*if(mod(n+1, k+1)=0, 1, 0)*10^k}
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CROSSREFS
| Cf. A051731, A081295, A048272, A101561, A101562.
Sequence in context: A202833 A174509 A103461 * A007133 A183518 A083452
Adjacent sequences: A101560 A101561 A101562 * A101564 A101565 A101566
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Dec 07 2004
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