|
%I #10 Apr 03 2014 03:09:09
%S 0,1,2,3,4,6,5,7,10,8,11,15,9,12,16,21,13,17,22,28,14,18,23,29,36,19,
%T 24,30,37,45,20,25,31,38,46,55,26,32,39,47,56,66,27,33,40,48,57,67,78,
%U 34,41,49,58,68,79,91,35,42,50,59,69,80,92,105,43,51,60,70,81,93,106,120
%N Numbers in n-th downward diagonal of triangle T : 0; 1, 2; 3, 4, 5; 6, 7, 8, 9; ...
%C Also the skewed triangle read by nonzero columns:
%C 1, 2
%C 0, 3, 4, 5
%C 0, 0, 6, 7, 8, 9
%C 0, 0, 0, 10,11,12,13,14
%C ... (offset 0,0), - _Ralf Stephan_, Mar 09 2014
%F a(n) = A091995(n+1)-1.
%F As skewed triangle: T(n,k) = (n+1)*(n+2)/2 + k-n, for n <= k <= 2n+2. - _Ralf Stephan_, Mar 09 2014
%Y See also A091018 (upward diagonal).
%K easy,nonn
%O 0,3
%A _Philippe Deléham_, Feb 25 2004
|
