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

1,1

Links

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

Example

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

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 *)

Prog

(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

Crossrefs

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

Sequence in context: A223458 A243429 A345346 * A284290 A045710 A090152

Adjacent sequences: A062666 A062667 A062668 * A062670 A062671 A062672

Keyword

base,easy,nonn

Author

Erich Friedman, Jul 04 2001

Extensions

Offset corrected by Amiram Eldar, Nov 07 2019

Example corrected by Harvey P. Dale, Jun 05 2021

Status

approved