A345280 - OEIS

%I #5 Jun 12 2021 22:34:52

%S 0,3,5,3,7,8,11,3,5,10,13,8,17,14,12,3,19,8,23,10,16,16,29,8,7,20,5,

%T 14,31,15,37,3,18,22,18,8,41,26,22,10,43,19,47,16,12,32,53,8,11,10,24,

%U 20,59,8,20,14,28,34,61,15,67,40,16,3,24,21,71,22,34,21,73,8,79,44

%N a(n) = Sum_{p|n} nextprime(p), where nextprime(n) is the smallest prime > n.

%e a(15) = Sum_{p|15} nextprime(p) = nextprime(3) + nextprime(5) = 5 + 7 = 12.

%t Table[Sum[NextPrime[k] (PrimePi[k] - PrimePi[k - 1]) (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 100}]

%Y Cf. A151800 (nextprime v.2), A345281.

%K nonn

%O 1,2

%A _Wesley Ivan Hurt_, Jun 12 2021