A375533 a(n) = numerator of Sum_{i=1..n} 1/A038603(i).
0, 1, 5, 31, 247, 5891, 175669, 6639823, 290694979, 13885515383, 746406329689, 44593096214321, 3020489689357037, 222690147603898211, 17752712881208877899, 1486130275559909484787, 133315968357656471537153, 13025132201814060676912631, 2913672358303309675918969343, 663425761972477930761347977351, 152383524508438692136746106396609
Offset: 0
Examples
The first few sums are 0/1, 1/2, 5/6, 31/30, 247/210, 5891/4830, 175669/140070, 6639823/5182590, ...
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..313
- N. J. A. Sloane, A Nasty Surprise in a Sequence and Other OEIS Stories, Experimental Mathematics Seminar, Rutgers University, Oct 10 2024, Youtube video; Slides [Mentions this sequence]
Programs
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Mathematica
a[n_]:=Numerator[Sum[ 1/Part[ResourceFunction["OEISSequence"]["A038603"],i],{i,n}]]; Array[a,20] (* Stefano Spezia, Sep 06 2024 *)
Extensions
a(0) prepended by Alois P. Heinz, Oct 21 2024
Comments