cp's OEIS Frontend

A230104 Numbers k such that m + (product of digits of m) is never equal to k.

%I A230104 #16 Jan 09 2023 09:05:29
%S A230104 1,3,5,7,9,11,13,15,17,19,21,25,27,31,33,36,37,39,43,48,49,51,52,53,
%T A230104 57,59,61,63,64,69,71,72,73,76,77,79,82,83,84,87,91,93,96,97,99,111,
%U A230104 113,115,117,119,121,127,131,133,136,137,139,148,149,151,153,157,159,163,164,169,171,172,173,176,177,179,182,183
%N A230104 Numbers k such that m + (product of digits of m) is never equal to k.
%C A230104 Numbers missing from A230099.
%H A230104 Michael S. Branicky, <a href="/A230104/b230104.txt">Table of n, a(n) for n = 1..10000</a>
%H A230104 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a>
%o A230104 (PARI) f(n) = if (n, n + vecprod(digits(n)), 0); \\ A230104
%o A230104 isok(m) = for(i=1, m, if (f(i) == m, return(0))); return(1); \\ _Michel Marcus_, Jan 09 2023
%o A230104 (Python)
%o A230104 from math import prod
%o A230104 def b(n): return n + prod(map(int, str(n)))
%o A230104 def aupto(n): return sorted(set(range(n+1)) - set(b(m) for m in range(n+1)))
%o A230104 print(aupto(183)) # _Michael S. Branicky_, Jan 09 2023
%Y A230104 Cf. A230099, A230103, A230105.
%K A230104 nonn,base
%O A230104 1,2
%A A230104 _N. J. A. Sloane_, Oct 13 2013