The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A160948

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A160948

Numbers n that are multiples of the digital sum of n-1.
(history; published version)

#19 by Joerg Arndt at Fri Mar 08 11:58:06 EST 2024

STATUS

editing

approved

#18 by Paolo P. Lava at Fri Mar 08 06:44:53 EST 2024

MAPLE

select(n->frac(n/convert(convert(n-1, base, 10), `+`))=0, [$2..923]);

# Paolo P. Lava, Apr 17 2018

STATUS

approved

editing

#17 by Bruno Berselli at Wed Apr 18 02:55:16 EDT 2018

STATUS

proposed

approved

#16 by Michel Marcus at Wed Apr 18 01:40:06 EDT 2018

STATUS

editing

proposed

#15 by Michel Marcus at Wed Apr 18 01:39:57 EDT 2018

PROG

(PARI) isok(n) = (n != 1) && !(n % sumdigits(n-1)); \\ Michel Marcus, Apr 18 17 2018

Discussion

Wed Apr 18

01:40

Michel Marcus: forgot to sign

#14 by Michel Marcus at Wed Apr 18 01:39:34 EDT 2018

PROG

(PARI) isok(n) = (n != 1) && !(n % sumdigits(n-1)); \\ _Michel Marcus_, Apr 18 2018

STATUS

proposed

editing

#13 by Jon E. Schoenfield at Tue Apr 17 22:20:33 EDT 2018

STATUS

editing

proposed

#12 by Jon E. Schoenfield at Tue Apr 17 22:20:30 EDT 2018

NAME

Numbers n that are multiples of the digital sum of n-1.

COMMENTS

72 = 9 * ds(71) = 9x9*(7+1) =9x8 9*8; 144 = 18 * ds(143) = 18 * (1+4+3) = 18 * 8.

STATUS

proposed

editing

#11 by Muniru A Asiru at Tue Apr 17 11:51:55 EDT 2018

STATUS

editing

proposed

#10 by Muniru A Asiru at Tue Apr 17 11:51:12 EDT 2018

LINKS

Muniru A Asiru, <a href="/A160948/b160948.txt">Table of n, a(n) for n = 1..1000</a>

PROG

(GAP) a:=List(Filtered(List([2..700], m->[m, List(List(List([1..m], n->n-1), ListOfDigits), Sum)[m]]), i->i[1] mod i[2]=0), j->j[1]); # Muniru A Asiru, Apr 17 2018

STATUS

proposed

editing