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 A344672 #25 Dec 25 2021 12:04:20
%S A344672 0,1,2,2,3,4,5,5,6,8,9,7,8,12,15,13,14,14,15,13,18,24,25,17,19,27,29,
%T A344672 23,24,22,23,23,30,38,44,28,29,41,50,38,39,35,36,34,38,50,51,37,41,51,
%U A344672 60,52,53,49,57,49,62,78,79,43,44,66,72,58,68,68,69,65,78,78
%N A344672 a(n) = Sum_{primes p <=n} phi(floor(n/p)).
%H A344672 Michel Marcus, <a href="/A344672/b344672.txt">Table of n, a(n) for n = 1..10000</a>
%t A344672 a[n_] := Plus @@ EulerPhi[Floor[n/Select[Range[n], PrimeQ]]]; Array[a, 100] (* _Amiram Eldar_, Jul 05 2021 *)
%o A344672 (PARI) a(n) = my(s=0); forprime(p=2, n, s+=eulerphi(n\p)); s;
%Y A344672 Cf. A000010, A013939 (with k instead of phi(k)), A346111 (with sigma instead).
%Y A344672 Cf. A317625.
%K A344672 nonn
%O A344672 1,3
%A A344672 _Michel Marcus_, Jul 05 2021