This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A134128 #15 Apr 30 2024 01:47:32
%S A134128 2,5,17,58,129,5117,43201,329401,1459228,111461983,269553485,
%T A134128 316504138,734845192,6185946407,10731178047,22691403557,148086969623,
%U A134128 474635764987,6777574922490,30458710811303,215730284567463,761593685331414,5875984396617486,10893968395261326
%N A134128 a(n) = A007504(A134126(n)).
%C A134128 This is the prime partial sum just before the prime is added to achieve an integer mean as defined in A134125.
%H A134128 Amiram Eldar, <a href="/A134128/b134128.txt">Table of n, a(n) for n = 1..32</a>
%e A134128 The sequence begins with a(1) = 2 (to which 3 is added which leads to a sum 5 associated with A134125(1)).
%e A134128 a(4) = 58 (to which the prime 19 is added, a sum of 77, associated with A134125(4)).
%o A134128 (UBASIC) 10 'primes using counters 20 N=3:C=1:R=5:print 2;3,5 30 A=3:S=sqrt(N) 40 B=N\A 50 if B*A=N then N=N+2:goto 30 60 A=A+2:O=A 70 if A<=sqrt(N) then 40 80 C=C+1 90 R=R+N:T=R/C:U=R-N 100 if T=int(T) then print C;U;N;R;T:stop 110 N=N+2:goto 30
%o A134128 (PARI) lista(pmax) = {my(k = 0, s = 2); forprime(p = 3, pmax, k++; s += p; if(!(s % k), print1(s-p, ", ")));} \\ _Amiram Eldar_, Apr 30 2024
%Y A134128 Cf. A134125, A134126, A134127, A134129.
%K A134128 less,nonn
%O A134128 1,1
%A A134128 _Enoch Haga_, Oct 09 2007
%E A134128 Edited by _R. J. Mathar_, Apr 17 2009
%E A134128 a(21)-a(24) from _Amiram Eldar_, Apr 30 2024