A049786 - OEIS

%I #9 Sep 08 2022 08:44:58

%S 0,0,1,1,2,1,3,3,4,4,6,3,6,7,8,6,10,8,11,9,11,10,18,10,12,14,18,14,20,

%T 12,19,19,20,21,30,13,20,25,32,21,28,18,31,29,28,25,45,25,30,31,34,30,

%U 48,37,43,28,33,38,64,29,38,47,53,37,50,32

%N a(n) = T(n,n-1), array T as in A049783.

%H G. C. Greubel, <a href="/A049786/b049786.txt">Table of n, a(n) for n = 2..1000</a>

%F a(n) = Sum_{j=1..n-2} mod(n-1, floor((n-2)/j)). - _G. C. Greubel_, Dec 12 2019

%p seq( add(`mod`(n-1, floor((n-2)/j)), j=1..n-2), n=2..70); # _G. C. Greubel_, Dec 12 2019

%t Table[Sum[Mod[n-1, Floor[(n-2)/j]], {j, n-2}], {n,2,70}] (* _G. C. Greubel_, Dec 12 2019 *)

%o (PARI) vector(70, n, sum(j=1,n-1, lift(Mod(n, (n-1)\j))) ) \\ _G. C. Greubel_, Dec 12 2019

%o (Magma) [0] cat [ &+[((n-1) mod Floor((n-2)/j)): j in [1..n-2]]: n in [3..70]]; // _G. C. Greubel_, Dec 12 2019

%o (Sage) [sum( (n-1)%floor((n-2)/j) for j in (1..n-2)) for n in (2..70)] # _G. C. Greubel_, Dec 12 2019

%o (GAP) List([2..70], n-> Sum([1..n-2], j-> (n-1) mod Int((n-2)/j)) ); # _G. C. Greubel_, Dec 12 2019

%Y Cf. A049783, A049784, A049785, A049787, A049788, A049789.

%K nonn

%O 2,5

%A _Clark Kimberling_