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Search: id:A053308
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| 1, 9, 46, 175, 551, 1518, 3785, 8735, 18955, 39130, 77533, 148487, 276408, 502415, 895103, 1568062, 2708322, 4622488, 7811510, 13091798, 21791338, 36067176, 59419294, 97522270, 159571139, 260459265, 424302452, 690141333
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 189, 194-196.
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FORMULA
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a(n)=sum{C(n+8-i, n-2i; i=0 to [n/2]}; n >= 0; [x]=greatest integer in x.
a(n)=Sum_{k=1..n}{C(n-k+8,k+7)}, with n>=0 - Paolo P. Lava (ppl(AT)spl.at), Apr 16 2008
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EXAMPLE
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a(n)=a(n-1)+a(n-2)+C(n+7,7); n >= 0; a(-1)=0.
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MATHEMATICA
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lst={}; s0=s1=s2=s3=s4=s5=s6=s7=0; Do[s0+=a[n]; s1+=s0; s2+=s1; s3+=s2; s4+=s3; s5+=s4; s6+=s5; s7+=s6; AppendTo[lst, s7], {n, 0, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 10 2008]
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CROSSREFS
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Cf. A053296, A053295, A000045.
Sequence in context: A009294 A061620 A001781 this_sequence A034487 A035039 A001926
Adjacent sequences: A053305 A053306 A053307 this_sequence A053309 A053310 A053311
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KEYWORD
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easy,nonn
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AUTHOR
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Barry E. Williams, Mar 06 2000
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