A180012 - OEIS

A180012

a(n) = smallest k >= 1 such that k and k*n have the same digit sum.

1, 9, 9, 3, 9, 9, 3, 9, 9, 1, 99, 9, 9, 9, 9, 9, 9, 9, 6, 9, 54, 6, 9, 9, 6, 9, 9, 4, 9, 9, 33, 36, 99, 3, 9, 9, 3, 9, 9, 3, 27, 27, 24, 99, 9, 5, 9, 9, 9, 9, 63, 6, 27, 45, 2, 9, 9, 9, 9, 9, 33, 18, 18, 5, 18, 99, 3, 9, 9, 3, 72, 45, 7, 18, 18, 15, 99, 9, 9, 9, 63, 5, 27, 18, 6, 27, 36, 15, 9, 9, 11

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

OFFSET

1,2

LINKS

D. W. Wilson, Table of n, a(n) for n=1..10000

EXAMPLE

For all 1 < k < 99, k and 11*k have distinct digit sum. 99 and 99*11 = 1089 have the same digit sum 18. Therefore a(11) = 99.

CROSSREFS

Sequence in context: A088398 A083949 A007471 * A172504 A172502 A118739

Adjacent sequences: A180009 A180010 A180011 * A180013 A180014 A180015

KEYWORD

base,easy,nonn

AUTHOR

David W. Wilson, Aug 06 2010

STATUS

approved