The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A054785

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A054785

a(n) = sigma(2n) - sigma(n), where sigma is the sum of divisors of n, A000203.
(history; published version)

#53 by Michel Marcus at Fri Jan 19 04:54:45 EST 2024

STATUS

reviewed

approved

#52 by Joerg Arndt at Fri Jan 19 03:45:20 EST 2024

STATUS

proposed

reviewed

#51 by Amiram Eldar at Fri Jan 19 03:27:29 EST 2024

STATUS

editing

proposed

#50 by Amiram Eldar at Fri Jan 19 03:25:32 EST 2024

FORMULA

Sum_{k=1..n} a(k) ~ c * n^2, were where c = Pi^2/8 = 1.2337005... (A111003). - Amiram Eldar, Jan 19 2024

#49 by Amiram Eldar at Fri Jan 19 03:05:14 EST 2024

CROSSREFS

Cf. A000079, A000203, A000593, A111003, A002131, A320059.

#48 by Amiram Eldar at Fri Jan 19 03:04:41 EST 2024

LINKS

Octavio A. Agustín-Aquino, <a href="http://math.colgate.edu/~integers/x37/x37.pdf">Wang-Sun formula in GL(Z/2kZ)</a>, Integers (2023) , Vol. 23, (2023), #A37.

#47 by Amiram Eldar at Fri Jan 19 03:04:00 EST 2024

FORMULA

Sum_{k=1..n} a(k) ~ c * n^2, were c = Pi^2/8 = 1.2337005... (A111003). - Amiram Eldar, Jan 19 2024

CROSSREFS

Cf. A000203, A000593, A111003, A002131, A320059.

STATUS

approved

editing

#46 by Michael De Vlieger at Wed Jun 07 09:45:01 EDT 2023

STATUS

reviewed

approved

#45 by Michel Marcus at Wed Jun 07 09:32:23 EDT 2023

STATUS

proposed

reviewed

#44 by Michael De Vlieger at Wed Jun 07 08:57:42 EDT 2023

STATUS

editing

proposed