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Search: id:A101563
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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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+0
4
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| 1, 9, 101, 1009, 10001, 99909, 1000001, 10001009, 100000101, 999990009, 10000000001, 100000100909, 1000000000001, 9999999000009, 100000000010101, 1000000010001009, 10000000000000001, 99999999900099909
(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)*10^k}
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CROSSREFS
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Cf. A051731, A081295, A048272, A101561, A101562.
Sequence in context: A056002 A060150 A103461 this_sequence A007133 A083452 A081461
Adjacent sequences: A101560 A101561 A101562 this_sequence A101564 A101565 A101566
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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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