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A048819
Decimal expansion of one of four fixed points (mod 1) of Minkowski's question mark function.
4
4, 2, 0, 3, 7, 2, 3, 3, 9, 4, 2, 3, 2, 2, 3, 0, 7, 5, 6, 4, 0, 9, 9, 3, 0, 0, 6, 6, 4, 6, 2, 2, 1, 8, 7, 3, 9, 4, 9, 1, 8, 9, 8, 6, 6, 6, 0, 0, 6, 1, 1, 8, 7, 1, 2, 9, 1, 6, 5, 4, 6, 6, 4, 6, 8, 6, 5, 5, 3, 3, 7, 0, 8, 8, 5, 9, 7, 9, 0, 8, 0, 3, 5, 5, 7, 4, 3, 9, 0, 5, 6, 0, 3, 9, 2, 8, 3, 3, 6
OFFSET
0,1
COMMENTS
Other fixed points (mod 1) are 0, 1/2 and 1-A048819. - Joseph Biberstine (jrbibers(AT)indiana.edu), Jun 10 2006
REFERENCES
S. R. Finch, Mathematical Constants, Cambridge, 2003, Section 6.9 Minkowski-Bower constant, pp. 441-443.
LINKS
Jean-François Alcover, Graph of the question mark function.
Steven R. Finch, Minkowski's Question Mark Function [Broken link]
Steven R. Finch, Minkowski's Question Mark Function [From the Wayback machine]
Eric Weisstein's World of Mathematics, Minkowski-Bower Constant
Eric Weisstein's World of Mathematics, Minkowski's Question Mark Function
EXAMPLE
0.4203723394232230756409930066462218739491898666...
MATHEMATICA
digits = 99; n0 = 3; dx = 10^-n0; qm[x_] := (ac = Accumulate[ContinuedFraction[x, 200]]; 2 + 2*Sum[(-1)^n* 2^(-ac[[n]]), {n, 1, Length[ac]}]); x = dx; While[N[qm[x], digits+5] < x, x = x + dx]; x0 = x - dx; Do[dx = 10^-n; x = x0; While[N[qm[x], digits+5] < x, x = N[x + dx, digits+5]]; x0 = x - dx , {n, n0+1, digits}]; RealDigits[x0, 10, digits] // First (* Jean-François Alcover, Oct 13 2014 *)
RealDigits[x /. FindRoot[MinkowskiQuestionMark[x] - x, {x, .42, .421}, WorkingPrecision -> 200, MaxIterations -> 500], 10, 99][[1]] (* Eric W. Weisstein, Jan 06 2023 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Christian G. Bower, Apr 15 1999
STATUS
approved