|
|
|
|
3, 7, 59, 137, 277, 313, 499, 563, 619, 719, 787, 797, 919, 937, 971, 1013, 1217, 1283, 1373, 1409, 1439, 1451, 1621, 1747, 1789, 2207, 2237, 2267, 2393, 2417, 2441, 2591, 2707, 2797, 2801, 2939, 2999, 3251, 3529, 3769, 3847, 4201, 4441, 4447, 4597, 4643, 4721
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Primes p such that the sum of the first p primes is semiprime.
|
|
LINKS
|
|
|
EXAMPLE
|
7 is in the sequence because the sum of the first 7 primes is 2 + 3 + 5 + 7 + 11 + 13 + 17 = 58 = 2*29, which is semiprime.
|
|
MAPLE
|
with(numtheory): for n from 1 to 10000 do:s:=sum(‘ithprime(k)’, ’k’=1..n):if bigomega(s)=2 and type(n, prime)=true then printf(`%d, `, n):else fi:od:
|
|
MATHEMATICA
|
Select[Flatten[Position[If[PrimeOmega[#]==2, 1, 0]&/@Accumulate[ Prime[ Range[ 5000]]], 1]], PrimeQ] (* Harvey P. Dale, Jan 27 2022 *)
|
|
PROG
|
(PARI) isok(n) = isprime(n) && bigomega(vecsum(primes(n))) == 2; \\ Michel Marcus, Sep 18 2017
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|