

A211509


Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2=2nx*y.


2



0, 1, 0, 2, 3, 4, 4, 4, 8, 7, 6, 10, 10, 8, 16, 10, 11, 16, 14, 8, 22, 12, 18, 24, 18, 13, 26, 18, 20, 24, 24, 10, 36, 22, 20, 30, 29, 20, 42, 20, 22, 30, 36, 24, 44, 24, 28, 40, 38, 15, 48, 26, 34, 48, 38, 18, 50, 38, 42, 38, 44, 18, 66, 42, 35, 50, 38, 32, 68, 24, 36
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OFFSET

0,4


COMMENTS

For a guide to related sequences, see A211422.


LINKS

Table of n, a(n) for n=0..70.


MATHEMATICA

t[n_] := t[n] = Flatten[Table[w^2 + x*y  2 n, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 70}] (* A211509 *)


CROSSREFS

Cf. A211422.
Sequence in context: A108355 A057951 A076410 * A305594 A320778 A058277
Adjacent sequences: A211506 A211507 A211508 * A211510 A211511 A211512


KEYWORD

nonn


AUTHOR

Clark Kimberling, Apr 14 2012


STATUS

approved



