The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History forA054785

(Bold, blue-underlined text is anaddition; 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)

#53byMichel Marcusat Fri Jan 19 04:54:45 EST 2024

STATUS

reviewed

approved

#52byJoerg Arndtat Fri Jan 19 03:45:20 EST 2024

STATUS

proposed

reviewed

#51byAmiram Eldarat Fri Jan 19 03:27:29 EST 2024

STATUS

editing

proposed

#50byAmiram Eldarat Fri Jan 19 03:25:32 EST 2024

FORMULA

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

#49byAmiram Eldarat Fri Jan 19 03:05:14 EST 2024

CROSSREFS

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

#48byAmiram Eldarat 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.

#47byAmiram Eldarat 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

#46byMichael De Vliegerat Wed Jun 07 09:45:01 EDT 2023

STATUS

reviewed

approved

#45byMichel Marcusat Wed Jun 07 09:32:23 EDT 2023

STATUS

proposed

reviewed

#44byMichael De Vliegerat Wed Jun 07 08:57:42 EDT 2023

STATUS

editing

proposed