A244576 Sum of all proper divisors of all positive integers <= prime(n).

0, 0, 2, 7, 23, 38, 69, 89, 133, 227, 268, 397, 483, 536, 632, 821, 1018, 1125, 1355, 1511, 1633, 1890, 2077, 2406, 2906, 3150, 3263, 3509, 3680, 3960, 5026, 5319, 5854, 6003, 6909, 7130, 7761, 8345, 8681, 9381, 9986, 10351, 11456, 11771, 12212, 12481, 14128

Offset: 1

Author

Omar E. Pol, Jun 30 2014

Keywords

• nonn

Comments

Also sum of all proper divisors of all positive integers <= prime(n)-1.

Also zero together with the numbers that are repeated in A244049.

Crossrefs

Cf. A000040, A000203, A048050, A244049, A244578, A244583.

Programs

PARI

a(n) = sum(i=2, prime(n), sigma(i)-i-1); \\ Michel Marcus, Sep 29 2014

Formula

a(n) = A244049(A000040(n)-1) = A244049(A000040(n)).

a(n) ~ (Pi^2/12 - 1/2) * n^2 * log(n)^2. - Amiram Eldar, Mar 22 2024

Extensions

More terms from Michel Marcus, Sep 29 2014