A211514 Number of ordered triples (w,x,y) with all terms in {1,...,n} and 3*w^2=x*y.

0, 0, 0, 2, 4, 4, 6, 6, 8, 10, 10, 10, 16, 16, 16, 18, 22, 22, 24, 24, 26, 28, 28, 28, 34, 38, 38, 48, 50, 50, 52, 52, 56, 58, 58, 58, 64, 64, 64, 66, 68, 68, 70, 70, 72, 74, 74, 74, 86, 94, 98, 100, 102, 102, 112, 112, 114, 116, 116, 116, 122, 122, 122, 124

Offset

0,4

Comments

For a guide to related sequences, see A211422.

Links

Table of n, a(n) for n=0..63.

Mathematica

t[n_] := t[n] = Flatten[Table[3 w^2 - x*y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 90}]  (* A211514 *)
t/2                          (* integers *)

Crossrefs

Cf. A211422.

Sequence in context: A113638 A187323 A262504 * A111457 A161765 A232091

Adjacent sequences: A211511 A211512 A211513 * A211515 A211516 A211517

Keyword

nonn

Author

Clark Kimberling, Apr 14 2012

Status

approved