A212066 - OEIS

A212066

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

0, 0, 4, 24, 71, 166, 322, 571, 928, 1403, 2043, 2875, 3906, 5183, 6727, 8584, 10762, 13303, 16219, 19601, 23442, 27766, 32636, 38080, 44130, 50771, 58147, 66243, 75099, 84768, 95238, 106629, 118939, 132179, 146448, 161761, 178106

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OFFSET

0,3

COMMENTS

a(n)+A212065(n)=n^4. For a guide to related sequences, see A211795.

LINKS

Table of n, a(n) for n=0..36.

MATHEMATICA

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

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

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

Map[t[#] &, Range[0, 50]] (* A212066 *)

(* Peter J. C. Moses, Apr 13 2012 *)

CROSSREFS

Cf. A211795.

Sequence in context: A124350 A112611 A363092 * A336039 A364600 A181617

Adjacent sequences: A212063 A212064 A212065 * A212067 A212068 A212069

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 30 2012

STATUS

approved