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A212245 Number of (w,x,y,z) with all terms in {1,...,n} and w=xyz-2n. 2
0, 0, 0, 4, 12, 15, 21, 36, 45, 46, 64, 76, 88, 91, 114, 120, 144, 156, 153, 186, 204, 201, 235, 235, 268, 271, 289, 316, 334, 340, 361, 382, 408, 408, 444, 465, 465, 489, 519, 525, 576, 573, 589, 616, 652, 640, 664, 709, 736, 748, 760, 778, 826, 808 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

For a guide to related sequences, see A211795.

LINKS

Table of n, a(n) for n=0..53.

MATHEMATICA

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

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

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

Map[t[#] &, Range[0, 60]]  (* A212245 *)

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

CROSSREFS

Cf. A211795.

Sequence in context: A024354 A020883 A002365 * A046087 A081872 A120097

Adjacent sequences:  A212242 A212243 A212244 * A212246 A212247 A212248

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 08 2012

STATUS

approved

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Last modified January 16 21:37 EST 2019. Contains 319206 sequences. (Running on oeis4.)