A211432 Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2=x^2+y^2.

1, 9, 17, 25, 33, 57, 65, 73, 81, 89, 113, 121, 129, 153, 161, 185, 193, 217, 225, 233, 257, 265, 273, 281, 289, 329, 353, 361, 369, 393, 417, 425, 433, 441, 465, 489, 497, 521, 529, 553, 577, 601, 609, 617, 625, 649, 657, 665, 673, 681, 721, 745

Offset

0,2

Comments

For a guide to related sequences, see A211422.

Links

Table of n, a(n) for n=0..51.

Mathematica

t[n_] := t[n] = Flatten[Table[-w^2 + x^2 + y^2, {w, -n, n}, {x, -n, n}, {y, -n, n}]]
c[n_] := Count[t[n], 0]
t = Table[c[n], {n, 0, 70}]  (* A211432 *)
(t - 1)/8                    (* integers *)

Crossrefs

Cf. A211422.

Sequence in context: A017077 A004768 A226323 * A211422 A035198 A271186

Adjacent sequences: A211429 A211430 A211431 * A211433 A211434 A211435

Keyword

nonn

Author

Clark Kimberling, Apr 10 2012

Status

approved