A330580 Composite numbers n that divide the sum of all composite numbers <= n.

4, 9, 604, 1849, 7123, 29588, 71056, 317238, 945414, 1347895, 3567705, 4624025, 8518502, 1523051853, 4353560959, 7537630621, 24916885136, 41483524658, 513849020166, 1021228997529, 1137756574012, 1185967711155, 1581191501535, 1705826324526

Offset: 1

Author

Rémy Sigrist, Dec 18 2019

Keywords

• nonn
• more

Crossrefs

Cf. A002808, A007506 (prime variant), A330579.

Programs

PARI

s=0; k=0; forcomposite (c=4, oo, k++; s+=c; if (s%c==0, print1 (c", ")))

Formula

a(n) = A002808(A330579(n)).

Extensions

a(15)-a(24) from Giovanni Resta, Dec 20 2019