OFFSET
1,2
COMMENTS
If p is prime, a(p) = Sum_{p|p} nextprime(p/p) = 2.
EXAMPLE
a(20) = Sum_{p|20} nextprime(20/p) = nextprime(10) + nextprime(4) = 11 + 5 = 16.
MATHEMATICA
Table[Sum[NextPrime[n/k] (PrimePi[k] - PrimePi[k - 1]) (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Jun 12 2021
STATUS
approved