cp's OEIS Frontend

A369057 Total number of representations of natural numbers in range 1 .. 4n-1 as sums of the form p*q + p*r + q*r, with three odd primes p <= q <= r.

%I A369057 #21 Jan 23 2024 15:57:13
%S A369057 0,0,0,0,0,0,1,1,1,2,2,2,3,4,4,4,4,5,7,7,7,8,9,10,10,11,11,12,12,14,
%T A369057 15,15,16,17,17,17,19,21,22,22,22,24,24,24,24,25,26,28,30,31,32,32,33,
%U A369057 35,35,35,35,38,38,39,39,41,42,44,44,47,48,49,50,50,50,51,52,52,54,54,54,59,61,61,61,63,64,65,65,67
%N A369057 Total number of representations of natural numbers in range 1 .. 4n-1 as sums of the form p*q + p*r + q*r, with three odd primes p <= q <= r.
%C A369057 Terms a(10^n), for n=1..7 are: 2, 82, 1819, 34220, 628914, 11855507, 233030075, which gives a(n)/n ratios: 0.2, 0.82, 1.82, 3.42, 6.29, 11.86, 23.30, etc, Question: does the ratio just keep on growing?
%H A369057 Antti Karttunen, <a href="/A369057/b369057.txt">Table of n, a(n) for n = 1..20000</a>
%o A369057 (PARI)
%o A369057 \\ Needs also program from A369055:
%o A369057 A369057list(up_to) = { my(v=vector(up_to)); s = 0; for(n=1,up_to,s+=A369055(n); v[n] = s); (v); };
%o A369057 v369057 = A369057list(up_to);
%o A369057 A369057(n) = v369057[n];
%Y A369057 Partial sums of A369055.
%Y A369057 Cf. A369054.
%K A369057 nonn
%O A369057 1,10
%A A369057 _Antti Karttunen_, Jan 21 2024