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 A212136 Number of (w,x,y,z) with all terms in {1,...,n} and w*x+y*z>n^2. 2

%I

%S 0,1,7,25,60,126,222,387,599,903,1295,1830,2458,3322,4317,5539,6993,

%T 8773,10766,13198,15906,19095,22707,26879,31376,36684,42500,49024,

%U 56131,64205,72833,82742,93314,104934,117500,131277,146003,162489

%N Number of (w,x,y,z) with all terms in {1,...,n} and w*x+y*z>n^2.

%C A212136(n)+A212150(n)=n^4. For a guide to related sequences, see A211795.

%t t = Compile[{{n, _Integer}}, Module[{s = 0},

%t (Do[If[w*x + y*z > n^2, s = s + 1],

%t {w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];

%t Map[t[#] &, Range[0, 40]] (* A212136 *)

%t (* _Peter J. C. Moses_, Apr 13 2012 *)

%Y Cf. A211795.

%K nonn

%O 1,3

%A _Clark Kimberling_, May 07 2012

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Last modified February 27 01:52 EST 2020. Contains 332299 sequences. (Running on oeis4.)