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 A280247 #10 Jul 10 2025 19:39:27
%S A280247 1,2,5,9,19,37,58,122,203,403,458,2186,2264,3146,4946,9042,9178,35422,
%T A280247 35593,99593,107531,113581,113834,2768042,2770542,2782710,2802393,
%U A280247 3395097,3395503,29315503,29315968,30364544,30418994,30455986,30544186,574739770,574740436
%N A280247 Partial sums of A280246 (Product_{d|n} psi(d)).
%C A280247 psi(n) is the sum of totatives of n (A023896).
%F A280247 a(n) = Sum_{i=1..n} A280246(i).
%t A280247 Accumulate@ Table[Product[Total@ Select[Range@ d, CoprimeQ[d, #] &], {d, Divisors@ n}], {n, 37}] (* _Michael De Vlieger_, Dec 30 2016 *)
%o A280247 (Magma) [&+[&*[&+[h: h in [1..d] | GCD(h,d) eq 1]: d in Divisors(k)]: k in [1..n]]: n in [1..100]];
%Y A280247 Cf. A023896, A280246, A280248.
%K A280247 nonn
%O A280247 1,2
%A A280247 _Jaroslav Krizek_, Dec 30 2016