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Revision History for A269311

(Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A269311 Consider the arithmetic derivative of a number x. Take the sum of its digits. Repeat the process deleting the first addendum and adding the previous sum. The sequence lists the numbers that after some iterations reach x.
(history; published version)
#15 by Susanna Cuyler at Wed May 22 21:01:50 EDT 2019
STATUS

proposed

approved

#14 by Michel Marcus at Wed May 22 10:50:45 EDT 2019
STATUS

editing

proposed

#13 by Michel Marcus at Wed May 22 10:50:41 EDT 2019
MATHEMATICA

dn[n_] := If[Abs@n < 2, 0, n Total[#2/#1 & @@@ FactorInteger[Abs@n]]]; (* from _Michael Somos, _, Apr 12 2011 *)

STATUS

proposed

editing

#12 by Robert Price at Wed May 22 10:47:02 EDT 2019
STATUS

editing

proposed

#11 by Robert Price at Wed May 22 10:46:42 EDT 2019
MATHEMATICA

dn[n_] := If[Abs@n < 2, 0, n Total[#2/#1 & @@@ FactorInteger[Abs@n]]]; (* from Michael Somos, Apr 12 2011 *)

Select[Range[10^5], dn[#] >= 10 && (d = IntegerDigits[dn[#]]; While[Total[d] < #, d = Join[Rest[d], {Total[d]}]]; Total[d] == #) &] (* Robert Price, May 22 2019 *)

STATUS

approved

editing

#10 by Bruno Berselli at Thu Jan 18 09:55:23 EST 2018
STATUS

proposed

approved

#9 by Lars Blomberg at Thu Jan 18 09:19:26 EST 2018
STATUS

editing

proposed

#8 by Lars Blomberg at Thu Jan 18 09:14:45 EST 2018
DATA

8, 18, 21, 160, 1590, 2420, 18620, 69229, 83790, 279964, 494520, 598810, 676450, 1183147, 4233720, 5600348, 14217074, 20025836, 64278677, 425208387, 604048830, 750851470, 1981942354

EXTENSIONS

a(19)-a(23) from Lars Blomberg, Jan 18 2018

STATUS

approved

editing

#7 by N. J. A. Sloane at Tue Mar 01 23:44:25 EST 2016
STATUS

editing

approved

#6 by N. J. A. Sloane at Tue Mar 01 23:44:22 EST 2016
KEYWORD

nonn,base,less,more,changed

STATUS

proposed

editing

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Last modified August 18 19:26 EDT 2024. Contains 375273 sequences. (Running on oeis4.)