|
|
A274182
|
|
Semiprimes that are the sum of the first n odd primes for some n.
|
|
1
|
|
|
15, 26, 39, 158, 326, 566, 789, 961, 1159, 1262, 1369, 1478, 1591, 1718, 1849, 2582, 3085, 3829, 4659, 5587, 7697, 8891, 10189, 13885, 14695, 16838, 17281, 18187, 19111, 20057, 22546, 24131, 25798, 26938, 27515, 28102, 35566, 36886, 38919, 41739, 43199, 50885
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
26 appears in the sequence because 26 = 2*13 that is semiprime. Also, 3+5+7+11 = 26.
158 appears in the sequence because 158 = 2*79 that is semiprime. Also, 3+5+7+11+13+17+19+23+29+31 = 158.
|
|
MAPLE
|
P:= select(isprime, [seq(i, i=3..10^4, 2)]):
select(t -> numtheory:-bigomega(t)=2, ListTools:-PartialSums(P)); # Robert Israel, Sep 23 2019
|
|
MATHEMATICA
|
Select[a = 0; Table[a = a + Prime[k], {k, 2, 300}], PrimeOmega[#] == 2 &]
|
|
PROG
|
(PARI) s = 0; forprime(p=3, 1e4, s + = p; if (bigomega(s)==2, print1(s, ", ")))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|