OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 43 is a term because 43 = A062198(5) is prime.
MAPLE
SP:= select(t -> numtheory:-bigomega(t) = 2, [$2..10000]):
PSSP:= ListTools:-PartialSums(SP):
select(isprime, PSSP);
MATHEMATICA
Select[Accumulate @ Select[Range[1500], PrimeOmega[#] == 2 &], PrimeQ] (* Amiram Eldar, Aug 29 2021 *)
PROG
(Python)
from sympy import factorint, isprime
def aupto(limit):
alst, k, s = [], 1, 0
for k in range(1, limit+1):
if sum(factorint(k).values()) == 2:
s += k
if s > limit: break
if isprime(s): alst.append(s)
return alst
print(aupto(320000)) # Michael S. Branicky, Aug 29 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Aug 29 2021
STATUS
approved