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A066955 Number of unordered solutions of xy+yz+zx=n, x,y,z>0. 5
0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 2, 1, 1, 1, 2, 1, 2, 0, 2, 2, 2, 0, 3, 2, 1, 2, 3, 1, 3, 0, 3, 3, 2, 1, 4, 2, 1, 2, 4, 2, 4, 0, 2, 4, 3, 1, 5, 3, 2, 2, 4, 2, 3, 2, 4, 5, 2, 0, 6, 2, 3, 3, 5, 3, 4, 2, 2, 5, 4, 0, 7, 3, 2, 4, 5, 4, 4, 0, 5, 6, 4, 1, 6, 4, 2, 4, 6, 2, 6, 2, 4, 5, 2, 3, 8, 6, 2, 3, 6, 2, 7, 0, 5, 8, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,11

COMMENTS

a(A094379(n)) = n and a(m) = n for m < A094379(n). [Reinhard Zumkeller, Mar 23 2012]

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

PROG

(PARI) a(n)=sum(i=1, n, sum(j=1, i, sum(k=1, j, if(i*j+j*k+k*i-n, 0, 1))))

(Haskell)

a066955 n = length [(x, y, z) | x <- [1 .. a000196 (div n 3)],

                              y <- [x .. div n x],

                              z <- [y .. div (n - x*y) (x + y)],

                              x * y + (x + y) * z == n]

-- Reinhard Zumkeller, Mar 23 2012

CROSSREFS

Cf. A000196, A066360.

Sequence in context: A325613 A305054 A238097 * A089048 A329443 A263025

Adjacent sequences:  A066952 A066953 A066954 * A066956 A066957 A066958

KEYWORD

nonn,easy

AUTHOR

Colin Mallows, Jan 26 2002

EXTENSIONS

More terms from Benoit Cloitre, Feb 02 2003

STATUS

approved

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Last modified June 13 18:45 EDT 2021. Contains 345008 sequences. (Running on oeis4.)