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.
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
Keywords
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.
Links
- Ben Whitmore, Table of n, a(n) for n = 1..95
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.
Comments