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%I #16 Nov 29 2020 02:09:06
%S 1,3,5,7,9,13,15,17,19,21,25,27,30,31,36,37,39,40,43,48,49,51,52,53,
%T 57,59,61,63,64,69,71,72,73,76,79,82,83,84,87,90,91,93,96,97,103,105,
%U 113,115,117,119,121,127,131,136,137,139,148,149,151,153,157,159,163,164
%N Unattainable numbers: integers not expressible as k + product of nonzero digits of k (A063114).
%H Amiram Eldar, <a href="/A063425/b063425.txt">Table of n, a(n) for n = 1..10000</a>
%H Paul A. Loomis, <a href="http://facstaff.bloomu.edu/ploomis/sequences.html">An Interesting Family of Iterated Sequences</a>.
%H Paul A. Loomis, <a href="http://facstaff.bloomu.edu/ploomis/itseq4.ps">An Introduction to Digit Product Sequences</a>, J. Rec. Math., 32 (2003-2004), 147-151.
%H Paul A. Loomis, <a href="/A063108/a063108.pdf">An Introduction to Digit Product Sequences</a>, J. Rec. Math., 32 (2003-2004), 147-151. [Annotated archived copy]
%H <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a>
%t f[n_] := Block[{s = Sort[ IntegerDigits[n]]}, While[ s[[1]] == 0, s = Drop[s, 1]]; n + Times @@ s]; t = Table[0, {200}]; Do[ a = f[n]; If[a < 200, t[[a]]++ ], {n, 200}]; Select[ Range[ 200], t[[ # ]] == 0 &] (* _Robert G. Wilson v_, Jul 16 2004 *)
%Y Cf. A063114, A096347, A063425, A096922, A096923, A096924, A096925, A096926, A096927, A096928, A096929, A096930, A096931.
%K base,nonn
%O 1,2
%A _Robert G. Wilson v_, Aug 09 2001