A330579 Numbers k such that the k-th composite number divides the sum of the first k composite numbers.

1, 4, 493, 1565, 6210, 26375, 64019, 289862, 870828, 1244485, 3313113, 4300012, 7946206, 1447234860, 4147639664, 7190149312, 23828369695, 39710847388, 494027033160, 982853084580, 1095174951021, 1141650682059, 1522735118076, 1642938906044

Offset: 1

Author

Rémy Sigrist, Dec 18 2019

Keywords

• nonn
• more

Comments

This sequence corresponds to the positions of zeros in A330578.

Examples

			The first 4 composite numbers are: 4, 6, 8 and 9.
As 4 + 6 + 8 + 9 = 3*9, 4 belongs to the sequence.
		

Crossrefs

Cf. A024011 (prime variant), A330578, A330580.

Programs

PARI

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

Extensions

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