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A063691 Number of solutions to x^2 + y^2 + z^2 = n in positive integers. 3
0, 0, 0, 1, 0, 0, 3, 0, 0, 3, 0, 3, 1, 0, 6, 0, 0, 3, 3, 3, 0, 6, 3, 0, 3, 0, 6, 4, 0, 6, 6, 0, 0, 6, 3, 6, 3, 0, 9, 0, 0, 9, 6, 3, 3, 6, 6, 0, 1, 6, 6, 6, 0, 6, 12, 0, 6, 6, 0, 9, 0, 6, 12, 0, 0, 6, 12, 3, 3, 12, 6, 0, 3, 3, 12, 7, 3, 12, 6, 0, 0, 12, 3, 9, 6, 0, 15, 0, 3, 15 (list; graph; refs; listen; history; internal format)
OFFSET

0,7

LINKS

T. D. Noe, Table of n, a(n) for n = 0..10000

FORMULA

G.f.: (Sum_{m=1..inf} x^(m^2))^3.

EXAMPLE

a(5)=0; a(6)=3 because 1^2+1^2+2^2 = 1^2+2^2+1^2 = 2^2+1^2+1^2 = 6; a(27)=4 because 1^2+1^2+5^2 = 1^2+5^2+1^2 = 3^2+3^2+3^2 = 5^2+1^2+1^2 = 27;

CROSSREFS

Cf. A063725, A063730.

Sequence in context: A095104 A021337 A033685 * A075874 A181634 A178952

Adjacent sequences:  A063688 A063689 A063690 * A063692 A063693 A063694

KEYWORD

easy,nice,nonn

AUTHOR

Andrew A. Doroshev (andy(AT)ip.rsu.ru), Aug 23 2001

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Last modified February 15 02:38 EST 2012. Contains 205689 sequences.