A235228 Numbers whose sum of digits is 18.

99, 189, 198, 279, 288, 297, 369, 378, 387, 396, 459, 468, 477, 486, 495, 549, 558, 567, 576, 585, 594, 639, 648, 657, 666, 675, 684, 693, 729, 738, 747, 756, 765, 774, 783, 792, 819, 828, 837, 846, 855, 864, 873, 882, 891, 909, 918, 927, 936, 945, 954, 963

Offset: 1

Author

Vincenzo Librandi, Jan 05 2014

Keywords

• nonn
• base
• easy

Comments

A007953(a(n)) = 18; number of repdigits = #{99,666,333333,222222222,1^18} = A242627(18) = 5. - Reinhard Zumkeller, Jul 17 2014

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A052217 - A052224, A061423, A143164, A166311, A166370, A166459.

Cf. A011557 (1), A052216 (2), A052217 (3), A052218 (4), A052219 (5), A052220 (6), A052221 (7), A052222 (8), A052223 (9), A052224 (10), A166311 (11), A235151 (12), A143164 (13), A235225(14), A235226 (15), A235227 (16), A166370 (17), A166459 (19), A235229 (20).

Cf. A242614, A242627.

Programs

Haskell

a235228 n = a235228_list !! (n-1)
a235228_list = filter ((== 18) . a007953) [0..]
-- Reinhard Zumkeller, Jul 17 2014

Magma

[n: n in [1..1000] | &+Intseq(n) eq 18];

Mathematica

Select[Range[1000], Total[IntegerDigits[#]] == 18 &]

Formula

a(n) = 9*A279769(n). - M. F. Hasler, Dec 23 2016