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Search: id:A016127
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| A016127 |
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Expansion of 1/((1-2x)(1-5x)). |
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+0
5
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| 1, 7, 39, 203, 1031, 5187, 25999, 130123, 650871, 3254867, 16275359, 81378843, 406898311, 2034499747, 10172515119, 50862608363, 254313107351, 1271565667827, 6357828601279, 31789143530683
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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With leading zero, binomial transform of A002450. - Paul Barry (pbarry(AT)wit.ie), Apr 11 2003
The sequence of fractions a(n)/(n+1) is the 3rd binomial transform of the sequence of fractions J(n+1)/(n+1) where J(n) is A001045(n). - Paul Barry (pbarry(AT)wit.ie), Aug 05 2005
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FORMULA
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a(n) =(5^(n+1)-2^(n+1))/3 =sum_i{0<=i<=n}5^i*2^(n-1) =5a(n-1)+2^n =2a(n-1)+5^n. - Henry Bottomley (se16(AT)btinternet.com), Apr 07 2003
Binomial transform of A020989. - Paul Barry (pbarry(AT)wit.ie), May 18 2003
a(n)=sum{k=0..n, sum{j=0..n, 5^(n-j)*binomial(j, k)}}; a(n)=sum{k=0..n, 2^k*5^(n-k)}=sum{k=0..n, 5^k*2^(n-k)}; - Paul Barry (pbarry(AT)wit.ie), Aug 05 2005
For n>2, a(n) = 9*a(n-1) - 24*a(n-2) + 20*a(n-3). - Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 26 2007
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CROSSREFS
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Sequence in context: A026752 A026379 A026708 this_sequence A099460 A092923 A125786
Adjacent sequences: A016124 A016125 A016126 this_sequence A016128 A016129 A016130
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KEYWORD
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nonn
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AUTHOR
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njas
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