A227206 -id:A227206 - cp's OEIS frontend

A338256 Generalized Markoff numbers: union of numbers a, b, c, d, e satisfying the Markoff(5) equation a^2 + b^2 + c^2 + d^2 + e^2 = abcde.

1, 3, 4, 5, 9, 12, 23, 31, 33, 35, 44, 57, 60, 81, 107, 123, 157, 179, 204, 212, 273, 293, 311, 369, 391, 411, 417, 459, 555, 620, 657, 679, 1076, 1115, 1187, 1259, 1275, 1308, 1377, 1453, 1713, 1813, 1979, 2508, 2604, 2673, 2764, 2817, 2885, 3419, 3475, 3804, 3849

Offset: 1

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Giorgos Kalogeropoulos, Oct 18 2020

nonn

Every term of A229240 is a term of this sequence.

Also, union of positive integers satisfying Hurwitz equation (x_1)^2 + (x_2)^2 + ... + (x_n)^2 = z * x_1 * x_2 * ... * x_n for z=1 and n=5.

			{1259,35,4,3,3} is a solution and that is why 3,4,35,1259 belong to the sequence.

Cf. A229240, A229242, A229241, A227206, A002559.

div={1,3};limit=10^4;Monitor[Do[m=div[[{a,b,c,d}]];m1=Times@@m;m2=Tr[m^2];s=Sqrt[m1^2-4m2];x1=(m1-s)/2;x2=(m1+s)/2;If[IntegerQ[x1]&&x2

cp's OEIS Frontend

A338256 Generalized Markoff numbers: union of numbers a, b, c, d, e satisfying the Markoff(5) equation a^2 + b^2 + c^2 + d^2 + e^2 = abcde.

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cp's OEIS Frontend

A338256 Generalized Markoff numbers: union of numbers a, b, c, d, e satisfying the Markoff(5) equation a^2 + b^2 + c^2 + d^2 + e^2 = a*b*c*d*e.

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Mathematica

A338256 Generalized Markoff numbers: union of numbers a, b, c, d, e satisfying the Markoff(5) equation a^2 + b^2 + c^2 + d^2 + e^2 = abcde.