A211430 - OEIS

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A211430

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

1, 7, 15, 25, 35, 49, 63, 77, 93, 111, 129, 147, 165, 187, 209, 231, 253, 275, 299, 325, 351, 377, 403, 429, 455, 485, 515, 545, 575, 605, 635, 665, 697, 731, 765, 799, 833, 867, 901, 935, 969, 1007, 1045, 1083, 1121, 1159, 1197, 1235, 1273, 1311

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

For a guide to related sequences, see A211422.

LINKS

Table of n, a(n) for n=0..49.

MATHEMATICA

t[n_] := t[n] = Flatten[Table[w^2 + x + y, {w, -n, n}, {x, -n, n}, {y, -n, n}]]

c[n_] := Count[t[n], 0]

t = Table[c[n], {n, 0, 70}] (* A211430 *)

(t - 1)/2 (* integers *)

CROSSREFS

Cf. A211422.

Sequence in context: A329383 A284758 A334798 * A082111 A323483 A236582

Adjacent sequences: A211427 A211428 A211429 * A211431 A211432 A211433

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 10 2012

STATUS

approved