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A196362 Positive integers a for which there is a (-5/2)-Pythagorean triple (a,b,c) satisfying a<=b. 7
2, 3, 4, 5, 6, 6, 7, 7, 8, 9, 10, 10, 10, 10, 11, 11, 12, 12, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 18, 18, 18, 19, 19, 20, 20, 20, 20, 21, 21, 21, 22, 22, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 26, 26, 27, 27, 28, 28, 28, 28, 29, 30, 30, 30, 30, 30 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A195770 for definitions of k-Pythagorean triple, primitive k-Pythagorean triple, and lists of related sequences.

LINKS

Table of n, a(n) for n=1..70.

MATHEMATICA

z8 = 900; z9 = 250; z7 = 200;

pIntegerQ := IntegerQ[#1] && #1 > 0 &;

k = -5/2; c[a_, b_] := Sqrt[a^2 + b^2 + k*a*b];

d[a_, b_] := If[pIntegerQ[c[a, b]], {a, b, c[a, b]}, 0]

t[a_] := Table[d[a, b], {b, a, z8}]

u[n_] := Delete[t[n], Position[t[n], 0]]

Table[u[n], {n, 1, 15}]

t = Table[u[n], {n, 1, z8}];

Flatten[Position[t, {}]]

u = Flatten[Delete[t, Position[t, {}]]];

x[n_] := u[[3 n - 2]];

Table[x[n], {n, 1, z7}]  (* A196362 *)

y[n_] := u[[3 n - 1]];

Table[y[n], {n, 1, z7}]  (* A196363 *)

z[n_] := u[[3 n]];

Table[z[n], {n, 1, z7}]  (* A196364 *)

x1[n_] := If[GCD[x[n], y[n], z[n]] == 1, x[n], 0]

y1[n_] := If[GCD[x[n], y[n], z[n]] == 1, y[n], 0]

z1[n_] := If[GCD[x[n], y[n], z[n]] == 1, z[n], 0]

f = Table[x1[n], {n, 1, z9}];

x2 = Delete[f, Position[f, 0]]  (* A196365 *)

g = Table[y1[n], {n, 1, z9}];

y2 = Delete[g, Position[g, 0]]  (* A196366 *)

h = Table[z1[n], {n, 1, z9}];

z2 = Delete[h, Position[h, 0]]  (* A196367 *)

CROSSREFS

Cf. A195770, A196363, A196364, A196365.

Sequence in context: A132172 A080680 A005376 * A195879 A305398 A216522

Adjacent sequences:  A196359 A196360 A196361 * A196363 A196364 A196365

KEYWORD

nonn

AUTHOR

Clark Kimberling, Oct 01 2011

STATUS

approved

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Last modified May 26 17:17 EDT 2019. Contains 323597 sequences. (Running on oeis4.)