A033906 Sort then Add, a(1)=20.
20, 22, 44, 88, 176, 343, 677, 1354, 2699, 5398, 8987, 16876, 33554, 67009, 67688, 134476, 268943, 503632, 526988, 783877, 1161665, 2277331, 3500708, 3504286, 3738854, 7084642, 7329320, 7552699, 10109498, 10224397, 11447876, 22894654
Offset: 1
Crossrefs
Cf. A033860.
Programs
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Maple
A033906 := proc(n) option remember ; if n =1 then 20; else A070196(procname(n-1)) ; end if; end proc: seq(A033906(n),n=1..100) ; # R. J. Mathar, Feb 03 2025
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Mathematica
NestList[#+FromDigits[Sort[IntegerDigits[#]]]&,20,40] (* Harvey P. Dale, Oct 28 2017 *)
Formula
a(n)=A033905(n-1), n>2. [From R. J. Mathar, Oct 22 2008]