OFFSET
1,1
COMMENTS
43 is the first prime which is not a Chen prime, hence this sequence begins the same as prime sums of the first n primes (see A013916). The subset consisting of Chen prime partial sums of Chen primes begins a(1) = 3 = A109611(2), a(2) = 11 = A109611(5), a(3) = 29 = A109611(10), a(4) = 59 = A109611(10), a(5) = 101 = A109611(21), a(6) = 239 = A109611(40), a(7) = 809 = A109611(95). Which are the next Chen prime partial sums of Chen primes?
FORMULA
EXAMPLE
a(7) = 1+2+3+5+7+11+13+17+19+23+29+31+37+41+47+53+59+67+71+83 = 619 is prime, which is the sum of the first 19 Chen primes (starting with 1).
MAPLE
Contribution from R. J. Mathar, Feb 07 2010: (Start)
isA001358 := proc(n) return ( numtheory[bigomega](n) = 2 ); end proc:
isA109611 := proc(n) isprime(n) and ( isprime(n+2) or isA001358(n+2) ); end proc:
A109611 := proc(n) option remember; local a; if n = 1 then 2; else a := nextprime( procname(n-1) ) ; while not isA109611(a) do a := nextprime(a) ; end do ; return a; end if; end proc:
isA172102 := proc(n) if isprime(n) then for j from 1 do if A118482(j) > n then return false; elif A118482(j) = n then return true; end if; end do ; else false ; end if; end proc:
for n from 1 to 10000000 do if isA172102(n) then printf("%d, \n", n) ; end if; end do ; (End)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Jan 25 2010
EXTENSIONS
Extended by R. J. Mathar, Feb 07 2010
STATUS
approved