A052489 - OEIS

A052489

Largest number that is n times sum of its decimal digits.

0, 9, 18, 27, 48, 45, 54, 84, 72, 81, 90, 198, 108, 195, 126, 135, 288, 153, 162, 399, 180, 378, 396, 207, 216, 375, 468, 486, 588, 261, 270, 558, 576, 594, 408, 315, 648, 999, 684, 351, 480, 738, 756, 774, 792, 405, 966, 846, 864, 882, 450, 918, 936, 954

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

It is infinite, as pointed out by Dr. Geoffrey Landis: Clearly if you have one integer that is N times the sum of its decimal digits, then when you add a 0 to the end, you have an integer that is 10N times the sum of its decimal digits. - Jonathan Vos Post, Feb 06 2011

LINKS

Daniel Mondot, Table of n, a(n) for n = 0..9999

MATHEMATICA

p[n_] := 10(Length[IntegerDigits[n]]+1); a[0]=0; a[n_] := Catch[For[k = p[n]*n, k >= 0, k--, If[k == n*Total[IntegerDigits[k]], If[k == 0, Print["a(", n, ") not found"]]; Throw[k]]]]; Table[a[n], {n, 0, 1000}] (* Jean-François Alcover, Jul 19 2012 updated Oct 06 2016 after Daniel Mondot's observations *)

PROG

(PARI) a(n) = {nbd = 1; while (9*nbd*n > 10^nbd, nbd++); forstep(k=9*nbd*n, 1, -1, if (sumdigits(k)*n == k, return(k)); ); 0; } \\ Michel Marcus, Oct 05 2016

CROSSREFS

Cf. A003634, A003635, A052490.

Sequence in context: A224977 A195085 A329640 * A034033 A115552 A043322

Adjacent sequences: A052486 A052487 A052488 * A052490 A052491 A052492

KEYWORD

base,nonn,nice,look

AUTHOR

Henry Bottomley, Mar 16 2000

STATUS

approved