|
%I #5 Feb 15 2022 02:03:59
%S 1,-1,4,-1,-2,9,-1,-2,-3,16,-1,-2,-3,-4,25,-1,-2,-3,-4,-5,36,-1,-2,-3,
%T -4,-5,-6,49,-1,-2,-3,-4,-5,-6,-7,64
%N A002260 * A128064.
%C Row sums = the triangular numbers: (1, 3, 6, 10, ...).
%C Row sums of A128077 = A000326, the pentagonal numbers: (1, 5, 12, 22, 35, ...).
%F A002260 * A128064 as infinite lower triangular matrices. Retain the right border of A128077 and change the signs of all other terms to (-).
%e First few rows of the triangle:
%e 1;
%e -1, 4;
%e -1, -2, 9;
%e -1, -2, -3, 16;
%e ...
%Y Cf. A002260, A128064, A128077, A000326.
%K tabl,sign
%O 1,3
%A _Gary W. Adamson_, Feb 14 2007
|
