A272206 - OEIS

%I #27 May 22 2016 00:18:25

%S 1,2,2,3,4,4,5,6,7,7,8,9,10,10,11,12,12,13,14,14,15,16,16,17,18,19,19,

%T 20,21,21,22,23,23,24,25,26,26,27,28,28,29,30,30,31,32,32,33,34,35,35,

%U 36,37,37,38,39,39,40,41,41,42,43,43,44,45

%N Rounded barycenter of first n primes defined as a(n) = round(sum_{i=1..n}(i*prime(i)) / sum_{i=1..n}prime(i))

%F a(n) = round(sum_{i=1..n}(i*prime(i)) / sum_{i=1..n}prime(i)).

%F a(n) = round(A014285(n)/A007504(n)).

%t a[n_] := Sum[i*Prime[i], {i, 1, n}]/Sum[Prime[i], {i, 1, n}];

%t Table[a[n] // Round, {n, 1, 64}];

%o (PARI) a(n) = round(sum(k=1, n, k*prime(k))/ sum(k=1, n, prime(k))); \\ _Michel Marcus_, May 22 2016

%Y Cf. A007504, A014285.

%K nonn

%O 1,2

%A _Andres Cicuttin_, May 21 2016