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A181786 Number of inequivalent solutions to n^2 = a^2 + b^2 + c^2 with positive a, b, c. 6
0, 0, 0, 1, 0, 0, 1, 1, 0, 3, 0, 2, 1, 1, 1, 3, 0, 2, 3, 3, 0, 6, 2, 3, 1, 2, 1, 8, 1, 3, 3, 4, 0, 10, 2, 5, 3, 4, 3, 8, 0, 5, 6, 6, 2, 11, 3, 6, 1, 8, 2, 12, 1, 6, 8, 8, 1, 15, 3, 8, 3, 7, 4, 20, 0, 6, 10, 9, 2, 16, 5, 9, 3, 9, 4, 15, 3, 15, 8, 10, 0, 22, 5, 11, 6, 9, 6, 18, 2, 11, 11, 14, 3, 21, 6, 13, 1, 12, 8, 31, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,10

COMMENTS

Note that a(n)=0 for n=0 and the n in A094958.

Also note that a(2n)=a(n), e.g., a(1000)=a(500)=a(250)=a(125)=14. - Zak Seidov, Mar 02 2012

a(n) is the number of distinct parallelepipeds each one having integer diagonal n and integer sides. - César Eliud Lozada, Oct 26 2014

LINKS

Zak Seidov, Table of n, a(n) for n = 0..1000

MATHEMATICA

nn=100; t=Table[0, {nn}]; Do[n=Sqrt[a^2+b^2+c^2]; If[n<=nn && IntegerQ[n], t[[n]]++], {a, nn}, {b, a, nn}, {c, b, nn}]; Prepend[t, 0]

CROSSREFS

Cf. A016725, A016727, A181787, A181788

Sequence in context: A275326 A092926 A052311 * A164629 A100950 A021335

Adjacent sequences:  A181783 A181784 A181785 * A181787 A181788 A181789

KEYWORD

nonn

AUTHOR

T. D. Noe, Nov 12 2010

STATUS

approved

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Last modified March 26 06:49 EDT 2017. Contains 284111 sequences.