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 A330579 Numbers k such that the k-th composite number divides the sum of the first k composite numbers. 2

%I

%S 1,4,493,1565,6210,26375,64019,289862,870828,1244485,3313113,4300012,

%T 7946206,1447234860,4147639664,7190149312,23828369695,39710847388,

%U 494027033160,982853084580,1095174951021,1141650682059,1522735118076,1642938906044

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

%C This sequence corresponds to the positions of zeros in A330578.

%e The first 4 composite numbers are: 4, 6, 8 and 9.

%e As 4 + 6 + 8 + 9 = 3*9, 4 belongs to the sequence.

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

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

%K nonn,more

%O 1,2

%A _Rémy Sigrist_, Dec 18 2019

%E a(15)-a(24) from _Giovanni Resta_, Dec 20 2019

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Last modified November 29 18:41 EST 2021. Contains 349416 sequences. (Running on oeis4.)