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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.
1
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, 18, 13, 36, 36, 35, 33, 30, 26, 21, 15, 45, 45, 44, 42, 39, 35, 30, 24, 17, 55, 55, 54, 52, 49, 45, 40, 34, 27, 19, 66, 66, 65, 63, 60, 56, 51, 45, 38, 30, 21
OFFSET
0,2
COMMENTS
Row sums: A084990(n+1).
A158405(n) = A002262(n) + A002260(n). See the formula.
(Without its first column, A094728 is A120070, which could be built from positive A005563 and -A158894.)
FORMULA
a(n) = A094728(n+1) - A049780(n).
EXAMPLE
a(0) = 1, a(1) = 3, a(2) =3-0 = 3, a(3) = 6, a(4) =6-0= 6, a(5) =6-1= 5, ... .
Triangle:
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, 18, 13,
36, 36, 35, 33, 30, 26, 21, 15,
etc.
MATHEMATICA
Table[(n^2 - n)/2 - Prepend[Accumulate@ Range[0, n - 3], 0], {n, 12}] // Flatten (* Michael De Vlieger, Apr 12 2016 *)
KEYWORD
nonn,tabl
AUTHOR
Paul Curtz, Apr 12 2016
STATUS
approved