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A212052
Number of (w,x,y,z) with all terms in {1,...,n} and 4w*x=5*y*z.
2
0, 0, 0, 0, 0, 18, 26, 30, 46, 52, 104, 112, 148, 156, 176, 278, 342, 354, 406, 418, 562, 602, 642, 658, 794, 988, 1040, 1090, 1190, 1210, 1526, 1550, 1726, 1794, 1858, 2152, 2368, 2396, 2468, 2548, 2980, 3012, 3212, 3244, 3408, 3890, 3982, 4018
OFFSET
0,6
COMMENTS
See A211795 for a guide to related sequences.
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[4 w*x == 5 y*z, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]] (* A212052 *)
%/2 (* integers *)
(* Peter J. C. Moses, Apr 13 2012 *)
CROSSREFS
Cf. A211795.
Sequence in context: A350773 A229967 A212049 * A093018 A284493 A337523
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 29 2012
STATUS
approved