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 A115293 Row sums of correlation triangle for (1+x)^3/(1-x). 1

%I

%S 1,8,31,80,160,272,416,592,800,1040,1312,1616,1952,2320,2720,3152,

%T 3616,4112,4640,5200,5792,6416,7072,7760,8480,9232,10016,10832,11680,

%U 12560,13472,14416,15392,16400,17440,18512,19616,20752,21920,23120,24352

%N Row sums of correlation triangle for (1+x)^3/(1-x).

%C Row sums of number triangle A115292.

%C If Y_i (i=1,2,3,4,5) are 2-blocks of a (n+5)-set X then a(n-2) is the number of 7-subsets of X intersecting each Y_i (i=1,2,3,4,5). - _Milan Janjic_, Oct 28 2007

%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Two Enumerative Functions</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).

%F G.f.: (1+x)^5/(1-x)^3; a(n)=sum{k=0..n, sum{j=0..n, [j<=k]*A115291(k-j)*[j<=n-k]*A115291(n-k-j)}}.

%t LinearRecurrence[{3,-3,1},{1,8,31,80,160,272},50] (* _Harvey P. Dale_, Dec 03 2018 *)

%K easy,nonn

%O 0,2

%A _Paul Barry_, Jan 19 2006

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Last modified June 4 17:50 EDT 2020. Contains 334828 sequences. (Running on oeis4.)