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A211508 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2=n-x*y. 2

%I #4 Apr 19 2012 17:39:20

%S 0,0,1,2,2,4,4,6,5,6,8,8,8,12,8,10,12,12,11,16,12,16,16,12,16,20,14,

%T 16,22,20,16,24,17,22,24,16,22,30,16,24,30,26,20,28,26,28,32,18,26,38,

%U 21,30,36,28,28,34,30,36,34,26,34,46,20,28,46,36,32,40,30,42,40

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

%C For a guide to related sequences, see A211422.

%t t[n_] := t[n] = Flatten[Table[w^2 + x*y - n, {w, 1, n}, {x, 1, n}, {y, 1, n}]]

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

%t t = Table[c[n], {n, 0, 80}] (* A211508 *)

%Y Cf. A211422.

%K nonn

%O 0,4

%A _Clark Kimberling_, Apr 14 2012

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Last modified March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)