I will use this post for a list of conclusions drawn from MRB constant N and the many similar approximations that I have found.
Let x= MRB Constant. Each approximation is followed by a maple input so you can verify these approximations.
The digits of accuracy (D.O.A.) might seem embellished by 1 digit because it is computed by the reciprocal of the magnitude of error. For instance, The Champernowne Constant = 0.1234567891011121314151617181920212223243..., and its approximation constructed from the MRB constant is (1/2)*(8647+1490*x)/(31589+24300*x). 0.1234567891011121314151617181920212223243-(1/2)*(8647+1490*x)/(31589+24300*x)= 9.79861545008*10^(-19). Thus, according to this rule, there are 19 digits worth of accuracy in the approximation. However, You could argue that counting the 0, only 18 digit actually match .
Shallit Constant = 
to all known digits of accuracy (26406/37505 + (26568*x)/7501)
Murata's Constant = 
to 17 digits of accuracy. (4*(7124-75*x))/(10057+27*x)
Zeta (2) = 
to 17 digits of accuracy. (1/2)*(358708+823*x)/(109034+251*x)
Silver constant = 
to 17 digits of accuracy. (4*(58709+145*x))/(72324+181*x)
Silver constant = 
to 17 D.O.A. (4/5)*(21265+2211*x)/(5352-55*x)
The domino tiling constant = 
to 17 digits of accuracy. (2*(5812+189*x))/(40451-1806*x)
Lemniscate constant = 
to 17 digits of accuracy. (12*(11123+50*x))/(50890+309*x)
Lemniscate constant = 
to 18 digits of accuracy. (2*(13981+2709*x))/(10819+1242*x)
The 2nd Lemniscate Constant = 
to 17 digits of accuracy. (8/3)*(-13556+839*x)/(-8783+576*x)
Plouffe's A-constant i.e.0.15915... = 
to 18 digits of accuracy. (1/2)*(24491+8*x)/(77485-2872*x)
Plouffe’s gamma constant = 
to 18 digits of accuracy. (1/380)*(32353+89*x)/(577+x)
Heath-Brown-Moroz constant = 
to 18 digits of accuracy. (73-39*x)/(49803+206*x)
Heath-Brown-Moroz Constant = 
to 19 digits of accuracy. (1/5)*(379+2*x)/(57285+1592*x)
Heath - Brown - Moroz Constant = 
to 18 D.O.A. (2/9)*(-272+27*x)/(-45587+3030*x)
Robbins constant = 
to 18 digits of accuracy. -(1848/308545)*exp(1)+41856/61709-(96/61709)*x
Robbins constant = 
to 17 digits of accuracy. (5/583)*(12430+343*x)/(161+5*x)
Robbins constant = 
to 17 digits of accuracy. (21/8)*(-5465+164*x)/(-21689+700*x)
The first Hundred-Dollar, Hundred-Digit Challenge = 
to 17 digits of accuracy. (2*(-5019+4*x))/(-31069+168*x)
The 2nd Hundred-Dollar Challenge constant = 
to 21 digits of accuracy. (2050903/1616720)*exp(1)-5/2+(1/4)*x
The 2 nd Hundred - Dollar Challenge constant = 
to 18 D.O.A.. (4*(-6017+4010*x))/(-25363+22400*x)
The decimal expansion of solution to problem #5 in the Trefethen challenge. =
(
) to 19 D.O.A. 1/96187((205030/27)*exp(1)-25-3*n)
The 6th Hundred-Dollar Challenge constant = 
to 17 digits of accuracy. (2651+232*x)/(43039+2568*x)
7th hundred-dollar challenge constant = 
to 17 digits of accuracy. -(1/4)*(-12233+267*x)/(4187+72*x)
8th hundred-dollar challenge constant = 
to 19 D.O.A. (10/3)*(-1038+517*x)/(-7688+1551*x)
10th Hundred-Digit Challenge constant = 
to 19 digits of accuracy. -7*x/(3424290+12707*x)
Probability that at least two people in a room of 23 share the same birthday = 
to 19 digits of accuracy. (1/3100)*(1113+874*x)/(1-x)
Probability that at least two people in a room of 23 share the same birthday = 
to 17 D.O.A. (2*(2879-330*x))/(10517+3135*x)
Universal Parabolic Constant = 
to 19 digits of accuracy. (1/10)*(318053+623*x)/(13855+27*x)
marvinrayburns.com
