A375523
a(n) = numerator of Sum_{i=1..n} 1/A171397(i).
Original entry on oeis.org
1, 3, 11, 25, 137, 49, 363, 761, 7129, 80939, 83249, 1109957, 1135697, 1159721, 2364487, 40916999, 13865893, 267536047, 271415923, 274943083, 6401288429, 6475652719, 32735212187, 33078431987, 300680459483, 43364113769, 1269032646901, 1280123549581, 40016557117411, 3666283538201
Offset: 1
The first few sums are 1, 3/2, 11/6, 25/12, 137/60, 49/20, 363/140, 761/280, 7129/2520, 80939/27720, 83249/27720, 1109957/360360, 1135697/360360, 1159721/360360, 2364487/720720, ...
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b:= n-> (l-> add(l[i]*11^(i-1), i=1..nops(l)))(convert(n,base,10)):
g:= proc(n) option remember; `if`(n<1, 0, g(n-1)+1/b(n)) end:
a:= n-> numer(g(n)):
seq(a(n), n=1..30); # Alois P. Heinz, Aug 30 2024
A375524
a(n) = denominator of Sum_{i=1..n} 1/A171397(i).
Original entry on oeis.org
1, 2, 6, 12, 60, 20, 140, 280, 2520, 27720, 27720, 360360, 360360, 360360, 720720, 12252240, 4084080, 77597520, 77597520, 77597520, 1784742960, 1784742960, 8923714800, 8923714800, 80313433200, 11473347600, 332727080400, 332727080400, 10314539492400, 937685408400, 937685408400
Offset: 1
The first few sums are 1, 3/2, 11/6, 25/12, 137/60, 49/20, 363/140, 761/280, 7129/2520, 80939/27720, 83249/27720, 1109957/360360, 1135697/360360, 1159721/360360, 2364487/720720, ...
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b:= n-> (l-> add(l[i]*11^(i-1), i=1..nops(l)))(convert(n,base,10)):
g:= proc(n) option remember; `if`(n<1, 0, g(n-1)+1/b(n)) end:
a:= n-> denom(g(n)):
seq(a(n), n=1..31); # Alois P. Heinz, Aug 30 2024
A375534
a(n) = denominator of Sum_{i=1..n} 1/A038603(i).
Original entry on oeis.org
1, 2, 6, 30, 210, 4830, 140070, 5182590, 222851370, 10474014390, 555122762670, 32752242997530, 2194400280834510, 160191220500919230, 12655106419572619170, 1050373832824527391110, 93483271121382937808790, 9067877298774144967452630, 2022136637626634327741936490
Offset: 0
The first few sums are 0/1, 1/2, 5/6, 31/30, 247/210, 5891/4830, 175669/140070, 6639823/5182590, ...
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a[n_]:=Denominator[Sum[ 1/Part[ResourceFunction["OEISSequence"]["A038603"],i],{i,n}]]; Array[a,18] (* Stefano Spezia, Sep 06 2024 *)
Showing 1-3 of 3 results.
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