The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A185584

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A185584

Positive numbers equal to the sum of the squares of their first k divisors for some k.
(history; published version)

#39 by Michael De Vlieger at Sat Jul 16 17:15:57 EDT 2022

STATUS

proposed

approved

#38 by Michel Marcus at Sat Jul 16 12:04:54 EDT 2022

STATUS

editing

proposed

#37 by Michel Marcus at Sat Jul 16 12:04:48 EDT 2022

MATHEMATICA

Select[Range[5000000], MemberQ[Accumulate[Divisors[#]^2], #]&] [From (* _Harvey P. Dale]_ *)

STATUS

approved

editing

#36 by Bruno Berselli at Mon Jan 20 18:24:29 EST 2014

STATUS

editing

approved

#35 by Bruno Berselli at Mon Jan 20 18:24:09 EST 2014

COMMENTS

For 130, k=4, 1^2+2^2+5^2+10^2 = 1+4+25+100 = 130

EXAMPLE

130 --> (1, 2, 5, 10) : 1^2+2^2+5^2+10^2 = 1+4+25+100 = 130.

1860 --> (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30).

148480 --> (1, 2, 4, 5, 8, 10, 16, 20, 29, 32, 40, 58, 64, 80, 116, 128, 145, 160, 232).

3039520 --> (1, 2, 4, 5, 8, 10, 11, 16, 20, 22, 32, 40, 44, 55, 80, 88, 110, 121, 157, 160, 232176, 220, 242, 314, 352, 440, 484, 605, 628, 785, 880).

3039520 (1, 2, 4, 5, 8, 10, 11, 16, 20, 22, 32, 40, 44, 55, 80, 88, 110, 121, 157, 160, 176, 220, 242, 314, 352, 440, 484, 605, 628, 785, 880)

STATUS

proposed

editing

#34 by Donovan Johnson at Mon Jan 20 18:17:00 EST 2014

STATUS

editing

proposed

#33 by Donovan Johnson at Mon Jan 20 18:11:41 EST 2014

DATA

1, 130, 1860, 148480, 3039520, 4172437680, 5788838100, 38341734200, 41251514850, 54116036100, 78936002964, 1059758860356

COMMENTS

a(12) > 10^11676358763167556, 3238006053537840, 343869932366333100, 408390181577292600, 466477390306128600 and 5447947283895097800 are also terms. - Donovan Johnson, Feb 07 2011Jan 20 2014

PROG

for(n=1, 1e7, isA185584(n)&print1(n", ")) \\ _M. F. Hasler_

EXTENSIONS

a(12) from Donovan Johnson, Jan 20 2014

STATUS

approved

editing

#32 by Charles R Greathouse IV at Mon May 13 01:49:31 EDT 2013

EXTENSIONS

a(6) from _Charles R Greathouse IV, _, Feb 05 2011

Discussion

Mon May 13

01:49

OEIS Server: https://oeis.org/edit/global/1914

#31 by N. J. A. Sloane at Wed May 01 21:03:32 EDT 2013

EXTENSIONS

Edited by _N. J. A. Sloane, _, Feb 05 2011

Discussion

Wed May 01

21:03

OEIS Server: https://oeis.org/edit/global/1895

#30 by N. J. A. Sloane at Wed May 01 20:54:48 EDT 2013

COMMENTS

a(12) > 10^11. - _Donovan Johnson, _, Feb 07 2011

Discussion

Wed May 01

20:54

OEIS Server: https://oeis.org/edit/global/1889