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A211787 Number of (w,x,y,z) with all terms in {1,...,n} and w*x<=2*y*z. 3

%I #10 Dec 04 2016 19:46:28

%S 0,1,15,66,201,469,958,1735,2937,4656,7050,10242,14461,19813,26569,

%T 34904,45086,57293,71898,89050,109201,132534,159424,190167,225296,

%U 264966,309685,359823,415889,478142,547302,623514,707593,799821

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

%C a(n)+A211797(n)=n^4.

%C See A211795 for a guide to related sequences.

%H Bo Gyu Jeong, <a href="/A211787/b211787.txt">Table of n, a(n) for n = 0..200</a>

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

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

%t {w, 1, #}, {x, 1, #}, {y, 1, #},

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

%t Map[t[#] &, Range[0, 40]] (* A211787 *)

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

%Y Cf. A211795.

%K nonn

%O 0,3

%A _Clark Kimberling_, Apr 27 2012

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Last modified April 23 08:19 EDT 2024. Contains 371905 sequences. (Running on oeis4.)