A134128 a(n) = A007504(A134126(n)).

2, 5, 17, 58, 129, 5117, 43201, 329401, 1459228, 111461983, 269553485, 316504138, 734845192, 6185946407, 10731178047, 22691403557, 148086969623, 474635764987, 6777574922490, 30458710811303, 215730284567463, 761593685331414, 5875984396617486, 10893968395261326

Offset

1,1

Comments

This is the prime partial sum just before the prime is added to achieve an integer mean as defined in A134125.

Links

Amiram Eldar, Table of n, a(n) for n = 1..32

Example

The sequence begins with a(1) = 2 (to which 3 is added which leads to a sum 5 associated with A134125(1)).
a(4) = 58 (to which the prime 19 is added, a sum of 77, associated with A134125(4)).

Prog

(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
(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

Crossrefs

Cf. A134125, A134126, A134127, A134129.

Sequence in context: A149990 A149991 A149992 * A119254 A278394 A056679

Adjacent sequences: A134125 A134126 A134127 * A134129 A134130 A134131

Keyword

less,nonn

Author

Enoch Haga, Oct 09 2007

Extensions

Edited by R. J. Mathar, Apr 17 2009

a(21)-a(24) from Amiram Eldar, Apr 30 2024

Status

approved