a(n) = Sum_{1 <= x_1 <= x_2 <= ... <= x_n <= n} gcd(x_1, x_2, ... , x_n, n).
A343517
a(n) = Sum_{1 <= x_1 <= x_2 <= ... <= x_n <= n} gcd(x_1, x_2, ... , x_n, n).
Terms
- a(0) =1a(1) =4a(2) =12a(3) =42a(4) =130a(5) =506a(6) =1722a(7) =6622a(8) =24426a(9) =93427a(10) =352726a(11) =1359388a(12) =5200312a(13) =20097156a(14) =77567064a(15) =300787366a(16) =1166803126a(17) =4539197723a(18) =17672631918a(19) =68933307843a(20) =269129530770
External references
- oeis: A343517