OFFSET
1,2
COMMENTS
Sum of the primes q from the ordered pairs of prime numbers, (p,q), such that p <= n <= q < 2n.
FORMULA
EXAMPLE
a(5) = 36; there are 6 ordered pairs of prime numbers, (p,q), such that p <= 5 <= q < 10: (2,5), (2,7), (3,5), (3,7), (5,5), and (5,7). The sum of the corresponding prime parts q gives 5+7+5+7+5+7 = 36.
MATHEMATICA
Table[PrimePi[n] Sum[(2 n - k) (PrimePi[2 n - k] - PrimePi[2 n - k - 1]), {k, n}], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Apr 01 2022
STATUS
approved