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 A140694 #15 May 20 2025 00:22:15 %S A140694 1,4,9,6,25,6,49,12,24,10,121,9,169,14,15,24,289,16,361,15,21,22,529, %T A140694 18,120,26,72,21,841,30,961,48,33,34,35,24,1369,38,39,30,1681,42,1849, %U A140694 33,40,46,2209,36,336,48,51,39,2809,48,55,42,57,58,3481,45,3721 %N A140694 a(n) = A014963(n) * A063659(n). %C A140694 A140579 as an infinite lower triangular matrix * A063659 as a vector. %F A140694 a(n) = n^2 iff n is prime. %F A140694 a(n) = n iff mu(n) = 1. %e A140694 a(4) = A014963(4) * A063659(4) = 2 * 3 = 6. %t A140694 f[p_, e_] := If[e == 1, p, p^e - p^(e - 2)]; a[n_] := Exp[MangoldtLambda[n]] * Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, May 18 2025 *) %Y A140694 Cf. A008683, A014963, A063659, A140579. %K A140694 nonn,easy %O A140694 1,2 %A A140694 _Gary W. Adamson_ and _Mats Granvik_, May 23 2008 %E A140694 More terms from _Amiram Eldar_, May 18 2025