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 A061258 #13 Apr 13 2024 05:16:26
%S A061258 1,3,7,11,21,21,43,27,61,63,111,53,157,129,87,91,273,183,343,151,175,
%T A061258 333,507,117,521,471,547,305,813,261,931,347,447,819,483,431,1333,
%U A061258 1029,631,327,1641,525,1807,781,681,1521,2163,373,2101,1563,1095,1103,2757
%N A061258 a(n) = Sum_{d|n} d*psi(d), where psi(d) is reduced totient function, cf. A002322.
%H A061258 Reinhard Zumkeller, <a href="/A061258/b061258.txt">Table of n, a(n) for n = 1..10000</a>
%F A061258 a(n) = Sum_{k = 1..A000005(n)} (A027750(n,k)*A002322(A027750(n,k))). - _Reinhard Zumkeller_, Sep 02 2014
%t A061258 a[n_] := DivisorSum[n, # * CarmichaelLambda[#] &]; Array[a, 100] (* _Amiram Eldar_, Apr 13 2024 *)
%o A061258 (Haskell)
%o A061258 a061258 n = sum $ zipWith (*) ds $ map a002322 ds
%o A061258 where ds = a027750_row n
%o A061258 -- _Reinhard Zumkeller_, Sep 02 2014
%o A061258 (PARI) a(n) = sumdiv(n, d, d * lcm(znstar(d)[2])); \\ _Amiram Eldar_, Apr 13 2024
%Y A061258 Cf. A002322, A057660, A001001, A060640, A061259.
%Y A061258 Cf. A000005, A027750, A141258.
%K A061258 easy,nonn
%O A061258 1,2
%A A061258 _Vladeta Jovovic_, Apr 21 2001