A024455 - OEIS

%I #7 Mar 29 2017 19:43:53

%S 0,2,4,7,11,17,23,30,39,50,61,74,88,104,121,140,160,182,204,228,254,

%T 282,312,343,376,409,444,480,519,561,604,648,695,743,793,845,898,954,

%U 1011,1069,1130,1192,1256

%N [ (3rd elementary symmetric function of P(n))/(2nd elementary symmetric function of P(n)) ], where P(n) = {first n+2 primes}.

%H Robert Israel, <a href="/A024455/b024455.txt">Table of n, a(n) for n = 1..10000</a>

%p P:= [seq(ithprime(i),i=1..102)]:

%p PS:= ListTools:-PartialSums(P):

%p S2:= P[1]*P[2]:

%p S3:= 0:

%p for n from 1 to 100 do

%p   S3:= S3 + P[n+2]*S2;

%p   S2:= S2 + P[n+2]*PS[n+1];

%p   A[n]:= floor(S3/S2);

%p od:

%p seq(A[i],i=1..100); # _Robert Israel_, Mar 29 2017

%K nonn

%O 1,2

%A _Clark Kimberling_