A364578 a(n) is the smallest n-digit number whose sum of digits is n.

1, 11, 102, 1003, 10004, 100005, 1000006, 10000007, 100000008, 1000000009, 10000000019, 100000000029, 1000000000039, 10000000000049, 100000000000059, 1000000000000069, 10000000000000079, 100000000000000089, 1000000000000000099, 10000000000000000199

Offset: 1

Author

Roland Kneer, Aug 14 2023

Keywords

• nonn
• base
• easy

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A051885, A202270 (largest instead of smallest).

Programs

Mathematica

Table[Module[{t=10^n},While[Total[IntegerDigits[t]]!=n+1,t++];t],{n,0,20}] (* or *) Join[{1},10^Range[63]+Flatten[Table[(k+1) 10^n-1,{n,0,6},{k,9}]]] (* Harvey P. Dale, Mar 31 2024 *)

PARI

a(n) = my(k=10^(n-1)); while (sumdigits(k) != n, k++); k; \\ Michel Marcus, Aug 16 2023

Python

def a(n): m=(n-1)//9; return int("1"+"0"*(n-m-2)+str((n-1)%9)*(n>1)+"9"*m)
print([a(n) for n in range(1,21)]) # Michael S. Branicky, Aug 16 2023