A062668 Composite and every divisor (except 1) contains the digit 3.

39, 93, 309, 339, 393, 403, 713, 933, 939, 993, 1137, 1293, 1317, 1329, 1333, 1339, 1369, 1389, 1643, 1703, 1839, 1893, 2263, 2319, 2369, 2573, 3013, 3029, 3039, 3071, 3093, 3099, 3107, 3117, 3139, 3151, 3189, 3193, 3197, 3279, 3309, 3369, 3419, 3459

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

93 has divisors 1, 3, 31 and 93, all of which contain the digit 3.

Mathematica

fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 3460], !PrimeQ[#] && fQ[#, 3] &] (* Robert G. Wilson v, Jun 11 2014 *)

Prog

(Magma) [k:k in [2..3500]| forall{d:d in Set(Divisors(k)) diff {1}| 3 in Intseq(d)}]; // Marius A. Burtea, Nov 07 2019

Crossrefs

Cf. A062653, A062664, A062667, A062669, A062670, A062671, A062672, A062673, A062674, A062675, A062676, A062677, A062678, A062679, A062680.

Sequence in context: A039422 A043245 A044025 * A158339 A211499 A126077

Adjacent sequences: A062665 A062666 A062667 * A062669 A062670 A062671

Keyword

base,easy,nonn

Author

Erich Friedman, Jul 04 2001

Extensions

Offset corrected by Amiram Eldar, Nov 07 2019

Status

approved