A062670 Composite and every divisor (except 1) contains the digit 4.

1849, 6407, 14227, 14309, 14921, 16403, 16441, 17243, 18409, 18847, 19049, 19147, 20459, 20941, 21457, 21479, 21949, 22427, 23453, 25427, 27649, 30409, 30463, 31949, 34921, 40463, 40721, 43009, 44227, 44509, 45107, 49303, 58343, 59491

Offset

1,1

Links

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

Example

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

Mathematica

fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 59500], !PrimeQ[#] && fQ[#, 4] &] (* Robert G. Wilson v, Jun 11 2014 *)
d4Q[n_]:=CompositeQ[n]&&AllTrue[Rest[Divisors[n]], DigitCount[#, 10, 4]>0&]; Select[Range[ 60000], d4Q] (* Harvey P. Dale, Jun 20 2023 *)

Crossrefs

Cf. A062653, A062664, A062667, A062668, A062669, A062671, A062672, A062673, A062674, A062675, A062676, A062677, A062678, A062679, A062680.

Sequence in context: A237892 A326318 A115719 * A379455 A206468 A031764

Adjacent sequences: A062667 A062668 A062669 * A062671 A062672 A062673

Keyword

base,easy,nonn

Author

Erich Friedman, Jul 04 2001

Extensions

Offset corrected by Amiram Eldar, Nov 07 2019

Status

approved