The On-Line Encyclopedia of Integer Sequences (OEIS)

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A048253

a(n) is the number of integers whose sum of divisors is 6^n.
(history; published version)

#17 by Alois P. Heinz at Mon May 14 18:26:20 EDT 2018

STATUS

proposed

approved

#16 by Michael De Vlieger at Mon May 14 13:31:20 EDT 2018

STATUS

editing

proposed

#15 by Michael De Vlieger at Mon May 14 13:31:18 EDT 2018

MATHEMATICA

With[{s = Array[DivisorSigma[1, #] &, 6^8]}, Array[Count[s, 6^#] &, Log[6, Length@ s] + 1, 0]] (* Michael De Vlieger, May 14 2018 *)

STATUS

proposed

editing

#14 by Michel Marcus at Mon May 14 05:08:02 EDT 2018

STATUS

editing

proposed

#13 by Michel Marcus at Mon May 14 05:07:39 EDT 2018

PROG

(PARI) a(n) = sum(k=1, 6^n, sigma(k)==6^n); \\ Michel Marcus, May 14 2018

STATUS

proposed

editing

Discussion

Mon May 14

05:08

Michel Marcus: code is slow, but there were none ...

#12 by Jon E. Schoenfield at Sun May 13 21:53:03 EDT 2018

STATUS

editing

proposed

#11 by Jon E. Schoenfield at Sun May 13 21:53:01 EDT 2018

NAME

Number a(n) is the number of integers whose sum of divisors = is 6^n.

EXAMPLE

For n=3 Sigma[ , sigma(1,x ]k) = 6^3 = 216 holds for each of 5 integers: 102, 110, 142, 159 , and 187, that is for so a(3) = 5 integers.

STATUS

approved

editing

#10 by Charles R Greathouse IV at Sun Aug 28 18:23:39 EDT 2016

LINKS

Ray Chandler, <a href="/A048253/b048253.txt">Table of n, a(n) for n = 0..1000</a>

Discussion

Sun Aug 28

18:23

OEIS Server: https://oeis.org/edit/global/2561

#9 by N. J. A. Sloane at Tue Oct 15 22:30:22 EDT 2013

AUTHOR

Labos E. (labos(AT)ana.sote.hu)

Labos Elemer

Discussion

Tue Oct 15

22:30

OEIS Server: https://oeis.org/edit/global/2029

#8 by Russ Cox at Fri Mar 30 17:34:48 EDT 2012

EXTENSIONS

a(9)-a(14) from _Donovan Johnson (donovan.johnson(AT)yahoo.com), _, Sep 02 2008

Discussion

Fri Mar 30

17:34

OEIS Server: https://oeis.org/edit/global/163