%I #34 Aug 30 2024 19:32:22

%S 9,18,27,36,45,54,63,72,81,90,108,117,126,135,144,153,162,171,180,207,

%T 216,225,234,243,252,261,270,306,315,324,333,342,351,360,405,414,423,

%U 432,441,450,504,513,522,531,540,603,612,621,630,702,711,720,801,810

%N Numbers whose sum of digits is 9.

%C Any term of this sequence with an 11 appended cannot have 11 as prime factor. See A075154. [_Lekraj Beedassy_, Sep 27 2009]

%C A007953(a(n)) = 9; number of repdigits = #{9,333,1^9} = A242627(9) = 3. - _Reinhard Zumkeller_, Jul 17 2014

%C A010872(a(n)) = A010878(a(n)) = 0. - _Ilya Gutkovskiy_, Jun 04 2016

%H Alois P. Heinz, <a href="/A052223/b052223.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 terms from Vincenzo Librandi)

%t Select[Range[1500], Total[IntegerDigits[#]] == 9 &] (* _Vincenzo Librandi_, Mar 08 2013 *)

%o (Magma) [n: n in [1..1500] | &+Intseq(n) eq 9 ]; // _Vincenzo Librandi_, Mar 08 2013

%o (Haskell)

%o a052223 n = a052223_list !! (n-1)

%o a052223_list = filter ((== 9) . a007953) [0..]

%o -- _Reinhard Zumkeller_, Jul 17 2014

%Y Cf. A007953.

%Y Row n=9 of A245062.

%Y Cf. A011557 (1), A052216 (2), A052217 (3), A052218 (4), A052219 (5), A052220 (6), A052221 (7), A052222 (8), A052224 (10), A166311 (11), A235151 (12), A143164 (13), A235225(14), A235226 (15), A235227 (16), A166370 (17), A235228 (18), A166459 (19), A235229 (20).

%Y Cf. A242614, A242627.

%K nonn,base,easy

%O 1,1

%A _Henry Bottomley_, Feb 01 2000

%E More terms from Larry Reeves (Larryr(AT)acm.org), Sep 05 2000

%E Offset changed by _Bruno Berselli_, Mar 07 2013