OFFSET
1,1
COMMENTS
Modeled on the same concept as cumulative sums of squared primes in A098562.
FORMULA
Define the sequence s as s(j) = Sum_{k=1..j} floor(Pi*prime(k)) for j >= 1; then a(n) is the n-th prime in the sequence s.
MAPLE
Digits := 30 ; A117503 := proc(nmax) local a, pisum, p ; a := [] ; pisum := 0 ; p :=1 ; while nops(a) <=nmax do while true do pisum := pisum+floor(Pi*ithprime(p)) ; p := p+1 ; if isprime(pisum) then a := [op(a), pisum] ; break ; fi ; od : od : RETURN(a) ; end: a := A117503(30) ; # R. J. Mathar, Oct 26 2006
MATHEMATICA
Select[Accumulate[Floor[Pi Prime[Range[800]]]], PrimeQ] (* Harvey P. Dale, Jun 06 2022 *)
PROG
(UBASIC)
10 Ct=1
20 B=nxtprm(B)
30 C=int(pi(B))
40 D=D+C
41 print Ct, B, C, D
50 if D=prmdiv(D) then print D:stop
55 Ct=Ct+1
60 goto 20
CROSSREFS
KEYWORD
easy,nonn,less
AUTHOR
Enoch Haga, Mar 25 2006
EXTENSIONS
Edited by Jon E. Schoenfield, Sep 23 2018
STATUS
approved