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Triangle read by rows: a(1,1)=1. a(m,n) = a(m-1,n) + (sum of all terms in row m-1), for n<m. a(m,m) = sum of all terms in row m-1.
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%I #19 Sep 07 2024 15:40:25

%S 1,2,1,5,4,3,17,16,15,12,77,76,75,72,60,437,436,435,432,420,360,2957,

%T 2956,2955,2952,2940,2880,2520,23117,23116,23115,23112,23100,23040,

%U 22680,20160,204557,204556,204555,204552,204540,204480,204120,201600

%N Triangle read by rows: a(1,1)=1. a(m,n) = a(m-1,n) + (sum of all terms in row m-1), for n<m. a(m,m) = sum of all terms in row m-1.

%C The sum of all terms in row m is (m+1)!/2. So a(m,n) = a(m-1,n) + m!/2, or is m!/2 if n=m.

%C Sum of m-th row = A001710(m+1). [_Klaus Brockhaus_, Jun 02 2009]

%C First column is A014288. - _Franklin T. Adams-Watters_, Oct 19 2013

%e Triangle starts:

%e 1;

%e 2, 1;

%e 5, 4, 3;

%e 17, 16, 15, 12;

%e 77, 76, 75, 72, 60;

%o (Magma) S:=[1]; T:=S; for m in [2..9] do s:=&+T; T:=[ n lt m select T[n]+s else s: n in [1..m] ]; S:=S cat T; end for; S; // _Klaus Brockhaus_, Jun 02 2009

%Y Cf. A159927.

%K nonn,tabl

%O 1,2

%A _Leroy Quet_, Apr 26 2009

%E More terms from _Klaus Brockhaus_, Jun 02 2009