login
A375534
a(n) = denominator of Sum_{i=1..n} 1/A038603(i).
2
1, 2, 6, 30, 210, 4830, 140070, 5182590, 222851370, 10474014390, 555122762670, 32752242997530, 2194400280834510, 160191220500919230, 12655106419572619170, 1050373832824527391110, 93483271121382937808790, 9067877298774144967452630, 2022136637626634327741936490
OFFSET
0,2
COMMENTS
See A375533 (the numerators) for further information.
LINKS
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]
EXAMPLE
The first few sums are 0/1, 1/2, 5/6, 31/30, 247/210, 5891/4830, 175669/140070, 6639823/5182590, ...
MATHEMATICA
a[n_]:=Denominator[Sum[ 1/Part[ResourceFunction["OEISSequence"]["A038603"], i], {i, n}]]; Array[a, 18] (* Stefano Spezia, Sep 06 2024 *)
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
N. J. A. Sloane, Sep 06 2024
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Oct 21 2024
STATUS
approved