MRB Summand and Mathematica's HarmonicNumber
With PROVISO

Expected output

In[]:=
"First 10 HarmonicNumber values:"​​{1,(3/2),(11/6),(25/12),(137/60),(49/20),(363/140),(761/280),(7129/2520),(7381/2520)}​​​​""​​"HarmonicNumber[n] equals Sum[1/k]?"​​{True,True,True,True,True,True,True,True,True,True}​​​​""​​"MRB summand phi[x] = x^(1/x)-1"​​​​""​​"Harmonic-number generating function:"​​SeriesData[z,0,{1,3/2,11/6,25/12,137/60,49/20,363/140,761/280,7129/2520,7381/2520},1,11,1]​​​​""​​"Written directly with HarmonicNumber:"​​z+(3z^2/2)+(11z^3/6)+(25z^4/12)+(137z^5/60)+(49z^6/20)+(363z^7/140)+(761z^8/280)+(7129z^9/2520)+(7381z^10/2520)​​​​""​​"Do the coefficients equal HarmonicNumber[n]?"​​{True,True,True,True,True,True,True,True,True,True}​​​​""​​"MRB-Harmonic identity:"​​True​​​​""​​"MRB expansion from original formula:"​​1-z-z^2-(z^3/2)+(z^4/6)+(3z^5/4)+(131z^6/120)+(9z^7/8)+(1087z^8/1260)+(271z^9/720)-(2291z^10/10080)​​​​""​​"MRB expansion from HarmonicNumber:"​​1-z-z^2-(z^3/2)+(z^4/6)+(3z^5/4)+(131z^6/120)+(9z^7/8)+(1087z^8/1260)+(271z^9/720)-(2291z^10/10080)​​​​""​​"Exactly equal through order "10"? "True​​​​""​​"Exact closed-form identity for x > 0:"​​True​​​​""​​"Direct MRB term versus harmonic-GF continuation:"​​​​""​​"PROVISO:"​​"Sum[HarmonicNumber[n] z^n, {n, 1, Infinity}]"​​"converges only for |z| < 1."​​"For MRB integer terms use the analytic continuation"​​"-Log[1-z]/(1-z), not the divergent raw power series."
Out[]=
First 10 HarmonicNumber values:
Out[]=
1,
3
2
,
11
6
,
25
12
,
137
60
,
49
20
,
363
140
,
761
280
,
7129
2520
,
7381
2520

Out[]=
Out[]=
HarmonicNumber[n] equals Sum[1/k]?
Out[]=
{True,True,True,True,True,True,True,True,True,True}
Out[]=
Out[]=
MRB summand phi[x] = x^(1/x)-1
Out[]=
Out[]=
Harmonic-number generating function:
Out[]=
z+
3
2
z
2
+
11
3
z
6
+
25
4
z
12
+
137
5
z
60
+
49
6
z
20
+
363
7
z
140
+
761
8
z
280
+
7129
9
z
2520
+
7381
10
z
2520
+
11
O[z]
Out[]=
Out[]=
Written directly with HarmonicNumber:
Out[]=
z+
3
2
z
2
+
11
3
z
6
+
25
4
z
12
+
137
5
z
60
+
49
6
z
20
+
363
7
z
140
+
761
8
z
280
+
7129
9
z
2520
+
7381
10
z
2520
Out[]=
Out[]=
Do the coefficients equal HarmonicNumber[n]?
Out[]=
{True,True,True,True,True,True,True,True,True,True}
Out[]=
Out[]=
MRB-Harmonic identity:
Out[]=
True
Out[]=
Out[]=
MRB expansion from original formula:
Out[]=
1-z-
2
z
-
3
z
2
+
4
z
6
+
3
5
z
4
+
131
6
z
120
+
9
7
z
8
+
1087
8
z
1260
+
271
9
z
720
-
2291
10
z
10080
Out[]=
Out[]=
MRB expansion from HarmonicNumber:
Out[]=
1-z-
2
z
-
3
z
2
+
4
z
6
+
3
5
z
4
+
131
6
z
120
+
9
7
z
8
+
1087
8
z
1260
+
271
9
z
720
-
2291
10
z
10080
Out[]=
Out[]=
10? Exactly equal through order True
Out[]=
Out[]=
Exact closed-form identity for x > 0:
Out[]=
True
Out[]=
Out[]=
Direct MRB term versus harmonic-GF continuation:
Out[]=
Out[]=
PROVISO:
Out[]=
Sum[HarmonicNumber[n] z^n, {n, 1, Infinity}]
Out[]=
converges only for |z| < 1.
Out[]=
For MRB integer terms use the analytic continuation

Conclusion

We did not insert harmonic numbers into the MRB problem . They were already hidden inside the original expression x^(1/x).
By shifting the point x = 1 to z = 0, the exponent of the MRB summand turns into the standard generating function for the harmonic numbers .

Related documentation

Acknowledgement

This was found while searching for a closed for using GPT . The author checked and understood the code . He personally accepts all responsibility for all statements made in the notebook .