The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A224832

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A224832

Numbers k such that the sum of reciprocals of even divisors of k is an integer.
(history; published version)

#16 by OEIS Server at Wed Jun 26 04:19:36 EDT 2024

LINKS

Amiram Eldar, <a href="/A224832/b224832_1.txt">Table of n, a(n) for n = 1..1013</a>

#15 by Alois P. Heinz at Wed Jun 26 04:19:36 EDT 2024

STATUS

proposed

approved

Discussion

Wed Jun 26

04:19

OEIS Server: Installed first b-file as b224832.txt.

#14 by Antti Karttunen at Wed Jun 26 03:50:31 EDT 2024

STATUS

editing

proposed

#13 by Antti Karttunen at Wed Jun 26 03:50:24 EDT 2024

COMMENTS

Conjecture: if a(n) is a non-twice even perfect numbers, the sum of reciprocals of even divisors equals 2.

STATUS

proposed

editing

#12 by Amiram Eldar at Wed Jun 26 02:30:32 EDT 2024

STATUS

editing

proposed

#11 by Amiram Eldar at Wed Jun 26 02:05:35 EDT 2024

LINKS

Amiram Eldar, <a href="/A224832/b224832_1.txt">Table of n, a(n) for n = 1..1013</a>

#10 by Amiram Eldar at Wed Jun 26 02:01:24 EDT 2024

FORMULA

a(n) = 2*A325637(n). - Amiram Eldar, Jun 26 2024

CROSSREFS

Cf. A000668, A139256, A194771, A000668A325637.

#9 by Amiram Eldar at Wed Jun 26 02:00:43 EDT 2024

DATA

12, 56, 992, 16256, 60480, 65520, 4357080, 47139840, 67100672, 91065600, 285981696, 2758909440, 17179738112, 87722956800, 132867440640, 274877382656, 306007080960, 806062473216, 1409150457792, 363485766938112, 12177456042320640, 29884246553283840, 40316371715063808

KEYWORD

nonn,hard,changed

EXTENSIONS

a(17)-a(23) from Amiram Eldar, Jun 26 2024

#8 by Amiram Eldar at Wed Jun 26 02:00:05 EDT 2024

NAME

Numbers n k such that the sum of reciprocals of even divisors of n k is an integer.

STATUS

approved

editing

#7 by T. D. Noe at Mon Jul 22 00:57:03 EDT 2013

STATUS

proposed

approved