A332094 - OEIS

%I #23 Dec 20 2024 02:08:42

%S 1,2,17,22,27,142,31,9,97,666,83,604,1529,1906,791,367,3533,4238,5019,

%T 584,617,7822,8995,518,473,13342,1663,8324,3689,20662,23003,532,1655,

%U 31074,541,6218,2145,44354,48187,2613,18805,20330,65651,356,15083,80894,28979,23293

%N Numerator of the average distance among first n primes.

%F a(n) = numerator((2/(n*(n-1)))*Sum_{j=2..n} Sum_{i=1..j-1} (prime(j) - prime(i))).

%t nmax=64;

%t Table[Total[Flatten[Table[Table[Prime[k] - Prime[j], {j, 1, k - 1}], {k, 2, n}]]]/(n*(n - 1)/2), {n, 2, nmax}]//Numerator

%o (PARI) lista(nn) = {my(vp = primes(nn)); vector(nn-1, k, k++; numerator((2/(k*(k-1))*sum(j=2, k, sum(i=1, j-1, vp[j] - vp[i])))));} \\ _Michel Marcus_, Nov 21 2020

%Y Cf. A336814 (denominator), A338869, A339022, A062020.

%K nonn,frac

%O 2,2

%A _Andres Cicuttin_, Nov 20 2020