The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A246913 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A246913

Numbers n such that sigma(n+sigma(n)) = 6*sigma(n).
(history; published version)

#12 by Charles R Greathouse IV at Thu Sep 08 08:46:09 EDT 2022

PROG

(MAGMAMagma) [n:n in[1..10^7] | SumOfDivisors(n+SumOfDivisors(n))eq 6*SumOfDivisors(n)]

Discussion

Thu Sep 08

08:46

OEIS Server: https://oeis.org/edit/global/2944

#11 by Alois P. Heinz at Fri Sep 11 14:45:04 EDT 2015

STATUS

proposed

approved

#10 by Hiroaki Yamanouchi at Fri Sep 11 14:34:14 EDT 2015

STATUS

editing

proposed

#9 by Hiroaki Yamanouchi at Fri Sep 11 14:34:06 EDT 2015

DATA

831376, 3944688, 16956576, 17843616, 22591296, 25371360, 27870976, 51878736, 58877280, 64641984, 142990848, 164898720, 172821456, 181821024, 204330672, 276371200, 281613024, 301571424, 319848480, 326207700, 342237456, 346502520, 389165568, 389450880, 392110992

COMMENTS

a(310) > 10^11. - Hiroaki Yamanouchi, Sep 11 2015

LINKS

Hiroaki Yamanouchi, <a href="/A246913/b246913.txt">Table of n, a(n) for n = 1..309</a>

KEYWORD

nonn,more

nonn

EXTENSIONS

a(5)-a(25) from Hiroaki Yamanouchi, Sep 11 2015

STATUS

approved

editing

#8 by N. J. A. Sloane at Tue Sep 23 11:18:24 EDT 2014

STATUS

proposed

approved

#7 by Michel Marcus at Sun Sep 07 12:11:22 EDT 2014

STATUS

editing

proposed

Discussion

Sun Sep 07

12:51

Joerg Arndt: The definition appears random to me.  Can you indicate what makes this one interesting?

Sat Sep 13

16:55

Jaroslav Krizek: Sequence is byproduct from considerations on generalization of Sophie Germain primes (see A246857).

#6 by Michel Marcus at Sun Sep 07 12:05:40 EDT 2014

KEYWORD

nonn,more,changed

STATUS

proposed

editing

#5 by Derek Orr at Sun Sep 07 11:56:51 EDT 2014

STATUS

editing

proposed

#4 by Derek Orr at Sun Sep 07 11:56:48 EDT 2014

PROG

(PARI)

for(n=1, 10^7, if(sigma(n+sigma(n))==6*sigma(n), print1(n, ", "))) \\ Derek Orr, Sep 07 2014

CROSSREFS

Cf. A000203, A246456, A246909, A246910, A246911, -A246912, A246914.

STATUS

proposed

editing

#3 by Jaroslav Krizek at Sun Sep 07 08:01:22 EDT 2014

STATUS

editing

proposed

Discussion

Sun Sep 07

08:39

Michel Marcus: more