A199982 Composite numbers with digital product = 3.

1113, 1131, 1311, 3111, 13111, 31111, 111113, 111131, 111311, 1111113, 1111131, 1111311, 1113111, 1131111, 1311111, 3111111, 11111113, 11311111, 13111111, 31111111, 111111311, 111131111, 111311111, 113111111, 311111111, 1111111113, 1111111131, 1111111311

Offset: 1

Author

Jaroslav Krizek, Nov 13 2011

Keywords

• nonn
• base

Comments

Also composite numbers whose multiplicative digital root is 3. Complement of A107689 with respect to A034050.

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A107689 (primes with digital product = 3).

Cf. A034050 (numbers with digital product = 3).

Programs

Mathematica

Table[Select[FromDigits[Permutations[PadRight[{3},n,1]]],CompositeQ],{n,4,10}]//Flatten//Sort (* Harvey P. Dale, May 31 2025 *)

Extensions

Incorrect 111113111 removed by Sean A. Irvine, Jan 06 2025