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A271668 Triangle read by rows. The first column is A000217(n+1). From the second row we apply - A002262(n) for the following terms of the row.

%I A271668 #10 Apr 13 2016 00:14:56
%S A271668 1,3,3,6,6,5,10,10,9,7,15,15,14,12,9,21,21,20,18,15,11,28,28,27,25,22,
%T A271668 18,13,36,36,35,33,30,26,21,15,45,45,44,42,39,35,30,24,17,55,55,54,52,
%U A271668 49,45,40,34,27,19,66,66,65,63,60,56,51,45,38,30,21
%N A271668 Triangle read by rows. The first column is A000217(n+1). From the second row we apply - A002262(n) for the following terms of the row.
%C A271668 Row sums: A084990(n+1).
%C A271668 A158405(n) = A002262(n) + A002260(n). See the formula.
%C A271668 (Without its first column, A094728 is A120070, which could be built from positive A005563 and -A158894.)
%F A271668 a(n) = A094728(n+1) - A049780(n).
%e A271668 a(0) = 1, a(1) = 3, a(2) =3-0 = 3,  a(3) = 6, a(4) =6-0= 6, a(5) =6-1= 5, ... .
%e A271668 Triangle:
%e A271668 1,
%e A271668 3,   3,
%e A271668 6,   6,  5,
%e A271668 10, 10,  9,  7,
%e A271668 15, 15, 14, 12,  9,
%e A271668 21, 21, 20, 18, 15, 11,
%e A271668 28, 28, 27, 25, 22, 18, 13,
%e A271668 36, 36, 35, 33, 30, 26, 21, 15,
%e A271668 etc.
%t A271668 Table[(n^2 - n)/2 - Prepend[Accumulate@ Range[0, n - 3], 0], {n, 12}] // Flatten (* _Michael De Vlieger_, Apr 12 2016 *)
%Y A271668 Cf. A000096, A000217, A002260, A002262, A005408, A005563, A049780, A084990, A094728, A120070, A158405, A158894.
%K A271668 nonn,tabl
%O A271668 0,2
%A A271668 _Paul Curtz_, Apr 12 2016