A033896 Sort then Add, a(1) =9.

9, 18, 36, 72, 99, 198, 387, 765, 1332, 2565, 5121, 6246, 8712, 9990, 10989, 12888, 25776, 51453, 64908, 69597, 126396, 250065, 252621, 374877, 722655, 948222, 1170711, 1281888, 2410776, 2535453, 4870008, 4874796, 9342585, 11688174, 22834962, 45069651

Offset: 1

Author

N. J. A. Sloane, David W. Wilson

Keywords

• nonn
• base
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A033860, A066711.

Programs

Maple

A033896 := proc(n)
    option remember ;
    if n =1 then
        9;
    else
        A070196(procname(n-1)) ;
    end if;
end proc:
seq(A033896(n),n=1..100) ; # R. J. Mathar, Feb 03 2025

Mathematica

NestList[FromDigits[Sort[IntegerDigits[#]]]+#&,9,40] (* Harvey P. Dale, Aug 19 2014 *)

Python

from itertools import accumulate
def sta(anm1, _): return anm1 + int("".join(sorted(str(anm1))))
print(list(accumulate([9]*36, sta))) # Michael S. Branicky, Sep 18 2021