cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A371554 Consider primitive pairs of integers (b, c) with b > 0 such that x^5 + b*x + c = 0 is irreducible and solvable by radicals: sequence gives values of c.

Original entry on oeis.org

44, 12, 44, 32, 64, 1344, 576, 1344, 832, 275, 4170, 2375, 3750, 4060, 128700, 13243, 1510620, 24000, 3348800, 8788, 467961, 51072, 133440, 474214, 61500, 128700, 85683, 514098, 509197, 199927, 24000, 3720000, 21376538, 210990, 486343, 114244, 12681084
Offset: 1

Views

Author

Ben Whitmore, Mar 27 2024

Keywords

Comments

See A371553.

Examples

			a(1) = 44 because A371553(1) = 11, and x^5 + 11*x + 44 is irreducible and solvable by radicals, and (11, 44) is a primitive pair.
		

Crossrefs

For values of b see A371553.

Programs

  • Mathematica
    pairs = Join @@ Table[
      Select[{m, Abs[#1 - b] #2/5} & @@@
        Sort[SolveValues[x^2 - (6b + 5y^4)x + 25b^2 == 0 && y > 0, {x, y},
    Integers]],
        Max[Last /@ FactorInteger[GCD @@ #]] < 4 &&
        AllTrue[#, IntegerQ] &&
        IrreduciblePolynomialQ[x^5 + #1x + #2 & @@ #] &
      ],
      {b, 1, 1000}
    ];
    pairs[[All, 2]]

Formula

x^5 + A371553(n)*x + a(n) is irreducible and solvable by radicals.