A211512 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2=3x*y.

0, 0, 0, 2, 2, 2, 6, 6, 6, 8, 8, 8, 14, 14, 14, 16, 18, 18, 22, 22, 22, 24, 24, 24, 30, 32, 32, 38, 38, 38, 44, 44, 46, 48, 48, 48, 56, 56, 56, 58, 58, 58, 62, 62, 62, 66, 66, 66, 76, 80, 82, 84, 84, 84, 92, 92, 92, 94, 94, 94, 104, 104, 104, 108, 112, 112, 116

Offset

0,4

Comments

For a guide to related sequences, see A211422.

Links

Table of n, a(n) for n=0..66.

Mathematica

t[n_] := t[n] = Flatten[Table[w^2 - 3 x*y, {w, 1, n}, {x, 1, n}, {y, 1, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 70}]  (* A211512 *)
t/2                          (* integers *)

Crossrefs

Cf. A211422.

Sequence in context: A214078 A155453 A032558 * A139552 A376948 A292140

Adjacent sequences: A211509 A211510 A211511 * A211513 A211514 A211515

Keyword

nonn

Author

Clark Kimberling, Apr 14 2012

Status

approved