A352380 Numbers k such that no nonzero digit of 3*k divides 3*k.

9, 18, 19, 23, 26, 29, 69, 83, 89, 143, 149, 158, 159, 163, 166, 169, 186, 193, 196, 199, 203, 209, 219, 223, 229, 233, 236, 249, 253, 258, 260, 263, 269, 283, 286, 289, 290, 293, 298, 299, 319, 323, 326, 669, 683, 689, 743, 759, 763, 803, 809, 823, 829, 833, 849, 853, 859, 863, 869, 883, 893, 899

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Example

a(1) = 9 and 3*9 = 27 is not divisible by 2 or 7;
a(2) = 18 and 3*18 = 54 is not divisible by 5 or 4;
a(3) = 19 and 3*19 = 57 is not divisible by 5 or 7;
a(4) = 23 and 3*23 = 69 is not divisible by 6 or 9; etc.
31 is not in the sequence as 3*31 = 93 is divisible by 3.

Mathematica

q[n_] := AllTrue[IntegerDigits[3*n], # == 0 || !Divisible[3*n, #] &]; Select[Range[900], q] (* Amiram Eldar, Mar 14 2022 *)

Prog

(Python)
def ok(n): return not any(3*n%int(d)==0 for d in set(str(3*n)) if d!='0')
print([k for k in range(1, 900) if ok(k)]) # Michael S. Branicky, Mar 14 2022

Crossrefs

Cf. A038772, A352379, A352381, A352382.

Sequence in context: A202188 A352960 A060993 * A297267 A296711 A297144

Adjacent sequences: A352377 A352378 A352379 * A352381 A352382 A352383

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Mar 14 2022

Status

approved