don't use old, unstable formulas at all.
Mandelbulb3Dv17{
a.....S....O/...M7...2I...E7hlE.dK2yzqgDMbEI5y0EFpGIAzMjEz1U3aj77wjpy2ri.sDtCkuD
................................ViUz0veL2.2.......UH./..................y.2...wD
...Uz.........../MU0/....6............E2.....gmCT2.8RmpD/..........m/dkpXm1....U
z.UaNadD32../..........wz..................................2.....y1...sD...../..
.w1...sDt8rxAvP7LxXHUr1PHtsSyOf4.tVBG1pjKj8Y0FxAnqff.Xfzbo7Lzkq.mb7lkRcjllHeTMXo
ExHx/IR8tOjUy2RG4ggjZQpD......o0..............kD.2....sD..E.....................
.............oAnAt1...sD....zUmbo9.mTGj.c/8x0UEco9.eVGj.678x0Uico9...........ET.
.....6OFaz1.......kz.caOe/.U..6.P....A0....O....H1...A0...U8....f....U2....UJl5I
...U.0aZczzzzzzzMg2czX6dE1..0c..znCv..UoK/nl2xvj3sM93P58iz1...........U.8.EssjA.
.wUmc2beYz1.dA8E5Exwz0........../6U0.wzzz1...........s/...................E.0c..
zzzz.............0...................2U.8.kzzzD.................................
/6U0.wzzz1....................................Ak.1..z1kze6/k.1A..1Ak.b47.06U...U
.1gbqgdht0kaqaPiTT2U.06.zzzzzzmH.1Ak..6.zzzpYB8fR0...0AkMIbRsZ6..1Ak.HFS.1Ak..6U
.0c2x/Ak.1kzzzzz...y3q/.zz/k.1A.yz1yAT2.xzpaqa9.................................
E.E..E....E.....I....M....kLn/5OZ7LNdtaR.................................oU30...
...........................................pJmUJJJJlz.........zj........kz1.....
................................................................................
.....................2.....3....0....wZFjl4NdtqNIJ4Rm3qAY/......................
06............................zD........kz1.....................................
................................................................................
................................/....E/...U/....TB5QcJaQZZaPq/..................
..............E1K6......................Uz9........sz0........yDO9FkFJJJJz1.....
..............zD................................................................
..........................................E.....I....2....kLHBKMgZaPb/..........
..........................................kSIsuFVf5wz0........zD........kz1.....
...wz...........................................................................
........................................................}
This works with the latest version of SphereInv. To make it work, I swapped RAD2 and FOLDINGMODE values.