OFFSET
0,2
COMMENTS
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 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Paul Curtz, Apr 12 2016
STATUS
approved