A383934 Composite numbers that contain only nonprime digits and whose prime factors contain only nonprime digits.

1111, 1199, 1681, 1691, 1919, 1991, 4141, 4411, 4469, 4499, 4609, 4961, 6109, 6161, 6611, 6649, 6809, 8899, 8989, 9089, 9481, 9691, 10109, 10901, 11009, 11041, 11099, 11419, 11881, 14641, 14801, 16109, 16441, 16489, 16999, 18409, 18491, 18601, 18689

Offset

1,1

Links

Scott R. Shannon, Table of n, a(n) for n = 1..10000

Example

10109 is a term as 10109 = 11 * 919, and both the number and its prime factors only contain nonprime digits.

Mathematica

Select[Select[Range[20000], And[CompositeQ[#], NoneTrue[IntegerDigits[#], PrimeQ]] &], NoneTrue[Flatten[IntegerDigits /@ FactorInteger[#][[All, 1]] ], PrimeQ] &] (* Michael De Vlieger, Aug 23 2025 *)

Crossrefs

Cf. A084984, A018252, A387093, A000040.

Sequence in context: A290556 A343038 A359098 * A218042 A176670 A072434

Adjacent sequences: A383931 A383932 A383933 * A383935 A383936 A383937

Keyword

nonn,base

Author

Scott R. Shannon, Aug 17 2025

Status

approved