This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A074947 #17 Nov 24 2022 04:21:17 %S A074947 1,1,5,5,37,47,69,263,1321,1429,9901,17249,113741,161191,32867,158363, %T A074947 3157279,5777183,18358381,20649997,9258477,10610101,24266365, %U A074947 2411391361,2299685867,1072410923,22804031069,27841579901,395718022103 %N A074947 Numerators of Sum_{k=1..n} 1/lcm(n,k). %C A074947 a(n)/A074949(n) is the asymptotic density of numbers that are divisible by their digital root in base n+1 (e.g., A064807 for base 10). - _Amiram Eldar_, Nov 24 2022 %H A074947 Amiram Eldar, <a href="/A074947/b074947.txt">Table of n, a(n) for n = 1..2308</a> %e A074947 1, 1, 5/6, 5/6, 37/60, 47/60, 69/140, 263/420, 1321/2520, 1429/2520, ... %t A074947 a[n_] := Numerator @ Sum[1/LCM[k, n], {k, 1, n}]; Array[a, 30] (* _Amiram Eldar_, Jan 31 2021 *) %o A074947 (PARI) a(n)=numerator(sum(i=1,n,1/lcm(n,i))) %Y A074947 Cf. A064807, A074949 (denominators). %K A074947 easy,frac,nonn %O A074947 1,3 %A A074947 _Benoit Cloitre_, Oct 05 2002