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A269067 Numerator of the volume of d dimensional symmetric convex cuboid with constraints |x1 + x2 + ... xd| <= 1 and |x1|, |x2|, ..., |xd| <= 1. 1
2, 3, 16, 115, 88, 5887, 19328, 259723, 124952, 381773117, 41931328, 20646903199, 866732192, 467168310097, 2386873693184, 75920439315929441, 97261697912, 5278968781483042969, 2387693641959232, 9093099984535515162569, 10872995484706511008, 168702835448329388944396777, 38650653745373963289088 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Reference A. Dubickas shows that all the volume integrals are rational with V[d] <= 2^d.

LINKS

Table of n, a(n) for n=1..23.

R. Chela, Reducible Polynomials, Journal London Math. Soc. 38 (1963), pp 183-188 Eq. 7.

Arturas Dubickas, On the number of reducible polynomials of bounded naive height, Manuscripta Math. 144 (2014), pp 439-456, Eq. 4, 5 & Section 5.

Mathematica Stack Exchange, How to improve or optimize a volume integration over a cuboid

EXAMPLE

For d = 3 the volume is 16/3, for each volume we have V[1] = 2, V[2] = 3, V[3] = 16/3, V[4] = 115/12, V[5] = 88/5, V[6] = 5887/180, V[7] = 19328/315, V[8] = 259723/2240, V[9] = 124952/567, V[10] = 381773117/907200, etc.

MATHEMATICA

V[d_] := Integrate[Boole[Abs[Sum[x[i], {i, 1, d}]] <= 1],

  Table[x[i], {i, 1, d}] \[Element]

   Cuboid[Table[-1, {i, 1, d}], Table[+1, {i, 1, d}]] (* Lorenz H. Menke, Jr. *)

v[d_] := With[{a = Array[x, d]}, RegionMeasure @ ImplicitRegion[ a ∈ Cuboid[-Table[1, d], Table[1, d]] && -1 <= Total[a] <= 1, a]] (* Carl Woll *)

v[d_] := 2^(d+1)/(Pi) Integrate[Sin[t]^(d+1)/t^(n+1), {t, 0, Infinity}] (* Carl Woll *)

CROSSREFS

The denominator sequence is given by A266913.

Cf. A199832 The rational coefficient of the leading coefficient of the empirical rows duplicates these volume integrals in sequence.  This is not a proof.

Sequence in context: A012572 A254382 A067848 * A139802 A292207 A063666

Adjacent sequences:  A269064 A269065 A269066 * A269068 A269069 A269070

KEYWORD

nonn,frac

AUTHOR

Lorenz H. Menke, Jr., Feb 19 2016

EXTENSIONS

a(11)-a(23) from Lorenz H. Menke, Jr., May 10 2018

STATUS

approved

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Last modified July 10 12:34 EDT 2020. Contains 335576 sequences. (Running on oeis4.)