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%I #8 Apr 21 2023 17:14:27
%S 1,1,2,4,12,42,178,870,4830,29976,205572,1543210,12583242,110725638,
%T 1045664646,10547679660,113172039256,1286925785286,15459448549274,
%U 195616259182162,2600506074185090,36235386548738016,528084808585261568,8033872923106040478
%N Di-Boustrophedon transform of (1,0,0,0,...): Fill in an array by diagonals alternating in the 'up' and 'down' directions. The n-th diagonal starts with the n-th element of (1,0,0,0,...). When going in the 'up' direction the next element is the sum of the previous element of the diagonal and the previous two elements of the row the new element is in. When going in the 'down' direction the next element is the sum of the previous element of the diagonal and the previous two elements of the column the new element is in. The final element of the n-th diagonal is a(n).
%e Array begins:
%e 1 1 0 4 0 42 ...
%e 0 1 3 4 38 ...
%e 2 2 7 31 ...
%e 0 10 22 ...
%e 12 12 ...
%e 0 ...
%Y Cf. A000667, A059216, A062704, A063180, A063181.
%K easy,nonn
%O 1,3
%A _Floor van Lamoen_, Jul 09 2001
%E More terms from _Sean A. Irvine_, Apr 21 2023
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