A321771 Numbers whose digit product equals the number of their digits.

1, 12, 21, 113, 131, 311, 1114, 1122, 1141, 1212, 1221, 1411, 2112, 2121, 2211, 4111, 11115, 11151, 11511, 15111, 51111, 111116, 111123, 111132, 111161, 111213, 111231, 111312, 111321, 111611, 112113, 112131, 112311, 113112, 113121, 113211, 116111, 121113

Offset

1,2

Comments

Idea is similar to A061384, which uses addition instead of multiplication.

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000

Example

12 has two digits, and their product is also 2, as 1*2=2.

Mathematica

Select[Range[1000000], Length[IntegerDigits[#]] == Times @@ IntegerDigits[#] &] (* Amiram Eldar, Nov 21 2018 *)

Prog

(PARI) isok(n) = my(d=digits(n)); vecprod(d) == #d; \\ Michel Marcus, Nov 22 2018

Crossrefs

Cf. A061384.

Cf. A007954, A055642. Subsequence of A007602.

Subsequence of A052382 (zeroless numbers).

Sequence in context: A111066 A201015 A044005 * A225864 A134514 A030299

Adjacent sequences: A321768 A321769 A321770 * A321772 A321773 A321774

Keyword

nonn,base

Author

Ivan Stoykov, Nov 21 2018

Extensions

More terms from Amiram Eldar, Nov 21 2018

Status

approved