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A352379 Numbers k such that no nonzero digit of 2*k divides 2*k.

%I A352379 #22 Apr 05 2025 14:15:56
%S A352379 17,19,23,27,28,29,34,37,38,39,43,47,49,154,167,169,173,178,179,185,
%T A352379 187,188,190,193,194,197,199,203,215,217,223,227,229,233,235,237,239,
%U A352379 245,247,249,253,254,268,269,277,278,279,283,289,293,294,298,299,317,319,323,328,329,334,335,337,338,343
%N A352379 Numbers k such that no nonzero digit of 2*k divides 2*k.
%C A352379 There are no terms between and including 500 and 1500 and there are no terms between and including 5000 and 15000. - _Harvey P. Dale_, Apr 05 2025
%H A352379 Harvey P. Dale, <a href="/A352379/b352379.txt">Table of n, a(n) for n = 1..5000</a>
%e A352379 a(1) = 17 and 2*17 = 34 is not divisible by 3 or 4;
%e A352379 a(2) = 19 and 2*19 = 38 is not divisible by 3 or 8;
%e A352379 a(3) = 23 and 2*23 = 46 is not divisible by 4 or 6;
%e A352379 a(4) = 27 and 2*27 = 54 is not divisible by 5 or 4; etc.
%e A352379 31 is not in the sequence as 2*31 = 62 is divisible by 2.
%t A352379 q[n_] := AllTrue[IntegerDigits[2*n], # == 0 || !Divisible[2*n, #] &]; Select[Range[350], q] (* _Amiram Eldar_, Mar 14 2022 *)
%t A352379 nnzdQ[n_]:=NoneTrue[Mod[2 n,Select[IntegerDigits[2 n],#!=0&]],#==0&]; Select[Range[350],nnzdQ] (* _Harvey P. Dale_, Apr 05 2025 *)
%o A352379 (Python)
%o A352379 def ok(n): return not any(2*n%int(d)==0 for d in set(str(2*n)) if d!='0')
%o A352379 print([k for k in range(1, 344) if ok(k)]) # _Michael S. Branicky_, Mar 14 2022
%Y A352379 Cf. A038772, A352380, A352381, A352382.
%K A352379 base,nonn
%O A352379 1,1
%A A352379 _Eric Angelini_ and _Carole Dubois_, Mar 14 2022