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a(n+1) is smallest multiple of (sum of digits of a(n)) which is > a(n).
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%I #12 Jul 13 2013 12:02:05

%S 1,2,4,8,16,21,24,30,33,36,45,54,63,72,81,90,99,108,117,126,135,144,

%T 153,162,171,180,189,198,216,225,234,243,252,261,270,279,288,306,315,

%U 324,333,342,351,360,369,378,396,414,423,432,441,450

%N a(n+1) is smallest multiple of (sum of digits of a(n)) which is > a(n).

%C a(n) mod 9 = 0 for n > 8. [_Reinhard Zumkeller_, Dec 28 2011]

%H Reinhard Zumkeller, <a href="/A045776/b045776.txt">Table of n, a(n) for n = 0..10000</a>

%t nxt[n_]:=Module[{sd=Total[IntegerDigits[n]]},(Floor[n/sd]+1)sd]; NestList[nxt,1,60] (* _Harvey P. Dale_, Jul 28 2012 *)

%o (Haskell)

%o a045776 n = a045776_list !! n

%o a045776_list = iterate f 1 where

%o f x = head $ dropWhile (<= x) [q,2*q..] where q = a007953 x

%o -- _Reinhard Zumkeller_, Dec 28 2011

%Y Cf. A007953.

%K easy,nonn,base,nice

%O 0,2

%A _Erich Friedman_