A147829 Minimum number k for which the digital sum of k*n is 9*n.

0, 9, 99, 333, 7497, 99999, 333333, 2842857, 49999986, 111111111, 9999999999, 99909090909, 249999999999, 2299923076923, 21427857142857, 333333333333333, 2499999999999993, 11764705294117647, 111111111111111111, 1526315788947368421

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Maple

P:=proc(i) local j, k, n, ok, w; for n from 0 by 1 to i do j:=-1; ok:=1; while ok=1 do j:=j+1; w:=0; k:=n*j; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if w=9*n then ok:=0; print(j); fi; od; od; end: P(100);

Prog

(PARI) a(n) = {my(k = 0); while (sumdigits(k*n) != 9*n, k++); k; }; \\ Michel Marcus, Mar 21 2016

Crossrefs

Cf. A147822-A147828, A147830, A147831.

Sequence in context: A292739 A266022 A284691 * A116274 A116286 A306449

Adjacent sequences: A147826 A147827 A147828 * A147830 A147831 A147832

Keyword

easy,nonn,base

Author

Paolo P. Lava and Giorgio Balzarotti, Nov 14 2008

Extensions

Edited by Charles R Greathouse IV, Nov 01 2009

a(7)-a(12) from Donovan Johnson, Sep 16 2012

a(13)-a(19) from Chai Wah Wu, Mar 20 2016

Status

approved