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A128089 Denominators in inverse of triangle A128078 by rows, n * each term in n-th row of A126615.

%I A128089 #7 Feb 15 2022 07:49:36
%S A128089 1,4,4,6,18,9,8,24,48,16,10,30,60,100,25,12,36,72,120,180,36,14,42,84,
%T A128089 140,210,294,49,16,48,96,160,240,336,448,64,18,54,108,180,270,378,504,
%U A128089 648,81,20,60,120,200,300,420,560,720,900,100
%N A128089 Denominators in inverse of triangle A128078 by rows, n * each term in n-th row of A126615.
%C A128089 Row sums = A014820: (1, 8, 33, 96, 225, 456, ...).
%C A128089 Denominators of the inverse of A128078: (1/1; 1/4, 1/4; 1/6, 1/18, 1/9; 1/8, 1/24, 1/48, 1/16; ...).
%C A128089 Row sums of this triangle: 1/1, 1/2, 1/3, ...; e.g., (1/8 + 1/24 + 1/48 + 1/16) = 1/4.
%F A128089 Denominators in inverse triangular matrix of A128078, where A128078 = A002260 * A128064, = (1; -1, 4; -1, -2, 9; -1, -2, -3, 16; ...).
%e A128089 First few rows of the triangle:
%e A128089    1;
%e A128089    4,  4;
%e A128089    6, 18,  9;
%e A128089    8, 24, 48,  16;
%e A128089   10, 30, 60, 100,  25;
%e A128089   12, 36, 72, 120, 180,  36;
%e A128089   14, 42, 84, 140, 210, 294,  49;
%e A128089   16, 48, 96, 160, 240, 336, 448,  64;
%e A128089   ...
%e A128089 Row 4 = (8, 24, 48, 16) = 4 * (2, 6, 12, 4); where (2, 6, 12, 4) = row 4 of A126615.
%Y A128089 Cf. A128078, A014820, A006527, A126615, A002260, A128064.
%K A128089 nonn,tabl,frac
%O A128089 1,2
%A A128089 _Gary W. Adamson_, Feb 14 2007