A062669 Every divisor (except 1) contains the digit 4.

41, 43, 47, 149, 241, 347, 349, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 541, 547, 641, 643, 647, 743, 941, 947, 1049, 1249, 1409, 1423, 1427, 1429, 1433, 1439, 1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487

Offset: 1

Author

Erich Friedman, Jul 04 2001

Keywords

• base
• easy
• nonn

Examples

			1849 has divisors 1, 43 and 1849, the last two of which contain the digit 4.
		

Links

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

Crossrefs

Cf. A062653, A062664, A062667, A062668, A062670, A062671, A062672, A062673, A062674, A062675, A062676, A062677, A062678, A062679, A062680.

Programs

Magma

[k:k in [2..1500]| forall{d:d in Set(Divisors(k)) diff {1}| 4 in Intseq(d)}];// Marius A. Burtea, Nov 07 2019

Mathematica

fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 1500], fQ[#, 4] &] (* Robert G. Wilson v, Jun 11 2014 *)
Select[Range[2,1500],AllTrue[Rest[Divisors[#]],DigitCount[#,10,4]>0&]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 05 2021 *)

Extensions

Offset corrected by Amiram Eldar, Nov 07 2019

Example corrected by Harvey P. Dale, Jun 05 2021