Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #4 Apr 05 2012 18:14:47
%S 1,3,2,5,4,2,7,6,4,2,9,8,6,4,2,11,10,8,6,4,2,13,12,10,8,6,4,2,15,14,
%T 12,10,8,6,4,2,17,16,14,12,10,8,6,4,2,19,18,16,14,12,10,8,6,4,2,21,20,
%U 18,16,14,12,10,8,6,4,2
%N Triangle read by rows, A000012 * A136521 * A000012; 1<=k<=n.
%C Row sums = A028387: (1, 5, 11, 19, 29, 41,...)
%F Triangle read by rows, A000012 * A136521 * A000012; 1<=k<=n. A136521 = an infinite lower triangular matrix with (1,2,2,2,...) in the main diagonal the rest zeros.
%e First few rows of the triangle =
%e 1;
%e 3, 2;
%e 5, 4, 2;
%e 7, 6, 4, 2;
%e 9, 8, 6, 4, 2;
%e 11, 10, 8, 6, 4, 2;
%e 13, 12, 10, 8, 6, 4, 2;
%e 15, 14, 12, 10, 8, 6, 4, 2;
%e ...
%Y Cf. A136521, A028387.
%K nonn,tabl
%O 1,2
%A _Gary W. Adamson_ & _Roger L. Bagula_, Aug 26 2008