The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A341879 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A341879

a(n) is the largest d(k) such that sigma(k) = n, where d is the number of divisor function and sigma is the sum of divisors function.
(history; published version)

#30 by Michel Marcus at Wed Apr 28 02:05:13 EDT 2021

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reviewed

approved

#29 by Joerg Arndt at Wed Apr 28 02:02:33 EDT 2021

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proposed

reviewed

#28 by Amiram Eldar at Wed Apr 28 01:58:22 EDT 2021

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editing

proposed

#27 by Amiram Eldar at Wed Apr 28 01:51:54 EDT 2021

MATHEMATICA

a[n_] := Module[{dmax = 0}, Do[If[DivisorSigma[1, k] == n && (d = DivisorSigma[0, k]) > dmax, dmax = d], {k, 1, n}]; dmax]; Array[a, 100] (* Amiram Eldar, Apr 28 2021 *)

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approved

editing

#26 by Joerg Arndt at Tue Feb 23 01:55:15 EST 2021

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reviewed

approved

#25 by Michel Marcus at Tue Feb 23 00:14:46 EST 2021

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proposed

reviewed

#24 by Seiichi Manyama at Mon Feb 22 22:31:31 EST 2021

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editing

proposed

#23 by Seiichi Manyama at Mon Feb 22 22:31:01 EST 2021

LINKS

Seiichi Manyama, <a href="/A341879/b341879.txt">Table of n, a(n) for n = 1..10000</a>

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proposed

editing

#22 by Jon E. Schoenfield at Mon Feb 22 20:05:25 EST 2021

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editing

proposed

#21 by Jon E. Schoenfield at Mon Feb 22 20:05:23 EST 2021

EXAMPLE

k that satisfies sigma (k) = 12 is 6 or 11. d(6) = 4 and d(11) = 2. So a(12) = 4.

STATUS

approved

editing