OFFSET
1,1
COMMENTS
Euler bricks are cuboids all of whose edges and face-diagonals are integers.
REFERENCES
L. E. Dickson, History of the Theory of Numbers, vol. 2, Diophantine Analysis, Dover, New York, 2005.
P. Halcke, Deliciae Mathematicae; oder, Mathematisches sinnen-confect., N. Sauer, Hamburg, Germany, 1719, page 265.
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Euler brick
FORMULA
Integer edges a>b>c such that integer face-diagonals are d(a,b)=sqrt(a^2+b^2), d(a,c)=sqrt(a^2,c^2), d(b,c)=sqrt(b^2,c^2)
EXAMPLE
For n=1, the edges (a,b,c) are (240,117,44) and the diagonals (d(a,b),d(a,c),d(b,c)) are (267,244,125).
MATHEMATICA
ok[a_] := Catch[Block[{b, c, s}, s = Reduce[a^2 + b^2 == c^2 && b > 0 && c > 0, {b, c}, Integers]; If[s === False, Throw@ False, s = b /. List@ ToRules@ s]; Do[If[ IntegerQ@ Sqrt[s[[i]]^2 + s[[j]]^2], Throw@ True], {i, 2, Length@s}, {j, i - 1}]]; False]; Select[ Range[700], ok] (* Giovanni Resta, Nov 22 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Christopher Monckton of Brenchley, Oct 06 2011
STATUS
approved