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Search: id:A027818
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| 1, 14, 84, 336, 1050, 2772, 6468, 13728, 27027, 50050, 88088, 148512, 241332, 379848, 581400, 868224, 1268421, 1817046, 2557324, 3542000, 4834830, 6512220, 8665020, 11400480, 14844375, 19143306, 24467184, 31011904
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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Number of 13-subsequences of [ 1, n ] with just 6 contiguous pairs; g.f. (1+6x)/(1-x)^8
C(n+1, 1)*C(n+6, 6) - Zerinvary Lajos (zlaja(AT)freemail.hu), May 26 2005
a(n)=n*(n-1)*(n-2)*(n-3)*(n-4)*(n-5)^2/6!,n=>6 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 19 2006
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MAPLE
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[seq(n*(n-1)*(n-2)*(n-3)*(n-4)*(n-5)^2/6!, n=6..33)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 19 2006
a:=n->sum((binomial(4, j)+binomial(n, 6)), j=6..n): seq(a(n), n=6..33); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 12 2007
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MATHEMATICA
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f[n_]:=7*n+1; s1=s2=s3=s4=s5=s6=0; lst={}; Do[a=f[n]; s1+=a; s2+=s1; s3+=s2; s4+=s3; s5+=s4; s6+=s5; AppendTo[lst, s6], {n, 0, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 25 2009]
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CROSSREFS
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Cf. A093564 ((7, 1) Pascal, column m=7). Partial sums of A050403.
Cf. A062190.
Sequence in context: A008451 A033276 A006858 this_sequence A054149 A025607 A059600
Adjacent sequences: A027815 A027816 A027817 this_sequence A027819 A027820 A027821
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KEYWORD
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nonn
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AUTHOR
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thi ngoc dinh (via rkg(AT)cpsc.ucalgary.ca)
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