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%I #18 Feb 15 2015 00:11:58
%S 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,
%T 25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,36,
%U 35,34,33,32,31,30,29,28,27
%N Write numbers 1, then 2^2 down to 1, then 3^2 down to 1, then 4^2 down to 1 and so on.
%C 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
%F For 1 <= n <= 650, a(n) = -n + (t + 2)*(2*t^2 - t + 3)/6, where t = floor((3*n)^(1/3)+1/2).
%e From _Omar E. Pol_, Jan 20 2015: (Start)
%e Written as an irregular triangle in which row lengths are successive squares, the sequence begins:
%e 1;
%e 4, 3, 2, 1;
%e 9, 8, 7, 6, 5, 4, 3, 2, 1;
%e 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1;
%e ...
%e (End)
%t a253902[n_] := Flatten@ Table[Reverse[Range[i^2]], {i, n}]; a253902[6] (* _Michael De Vlieger_, Jan 19 2015 *)
%o (PARI) lista(nn=10) = {for (n=1, nn, forstep(k=n^2, 1, -1, print1(k, ", ");););} \\ _Michel Marcus_, Jan 20 2015
%Y Cf. A064866, A074279.
%K nonn,easy,tabf
%O 1,2
%A _Mikael Aaltonen_, Jan 18 2015
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