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Revision History for A319086

(Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A319086 a(n) = Sum_{k=1..n} k^2*sigma(k), where sigma is A000203.
(history; published version)
#27 by Alois P. Heinz at Sat Oct 21 17:21:52 EDT 2023
STATUS

proposed

approved

#26 by Chai Wah Wu at Sat Oct 21 17:21:36 EDT 2023
STATUS

editing

proposed

#25 by Chai Wah Wu at Sat Oct 21 17:21:34 EDT 2023
PROG

(Python)

from math import isqrt

def A319086(n): return ((-((s:=isqrt(n))*(s+1))**3*(2*s+1)>>1) + sum(k**2*(q:=n//k)*(q+1)*(2*k*(2*q+1)+3*q*(q+1)) for k in range(1, s+1)))//12 # Chai Wah Wu, Oct 21 2023

STATUS

approved

editing

#24 by Michael De Vlieger at Fri Oct 20 15:54:30 EDT 2023
STATUS

reviewed

approved

#23 by Stefano Spezia at Fri Oct 20 15:05:30 EDT 2023
STATUS

proposed

reviewed

#22 by Chai Wah Wu at Fri Oct 20 13:24:06 EDT 2023
STATUS

editing

proposed

#21 by Chai Wah Wu at Fri Oct 20 13:24:03 EDT 2023
PROG

(Python)

def A319086(n): return sum((k*(m:=n//k)*(m+1)>>1)**2 for k in range(1, n+1)) # Chai Wah Wu, Oct 20 2023

STATUS

approved

editing

#20 by Peter Luschny at Thu Nov 08 19:34:32 EST 2018
STATUS

reviewed

approved

#19 by Michel Marcus at Thu Nov 08 11:14:04 EST 2018
STATUS

proposed

reviewed

#18 by Daniel Suteu at Thu Nov 08 07:25:30 EST 2018
STATUS

editing

proposed

Discussion
Thu Nov 08 11:14 
Michel Marcus: sure

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Last modified August 21 02:07 EDT 2024. Contains 375342 sequences. (Running on oeis4.)