OFFSET
1,2
COMMENTS
Triangle read by rows in which row n lists the first n^2 positive integers in decreasing order, n >= 1. - Omar E. Pol, Jan 20 2015
FORMULA
For 1 <= n <= 650, a(n) = -n + (t + 2)*(2*t^2 - t + 3)/6, where t = floor((3*n)^(1/3)+1/2).
EXAMPLE
From Omar E. Pol, Jan 20 2015: (Start)
Written as an irregular triangle in which row lengths are successive squares, the sequence begins:
1;
4, 3, 2, 1;
9, 8, 7, 6, 5, 4, 3, 2, 1;
16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1;
...
(End)
MATHEMATICA
a253902[n_] := Flatten@ Table[Reverse[Range[i^2]], {i, n}]; a253902[6] (* Michael De Vlieger, Jan 19 2015 *)
PROG
(PARI) lista(nn=10) = {for (n=1, nn, forstep(k=n^2, 1, -1, print1(k, ", "); ); ); } \\ Michel Marcus, Jan 20 2015
CROSSREFS
KEYWORD
nonn,easy,tabf
AUTHOR
Mikael Aaltonen, Jan 18 2015
STATUS
approved