login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A321771 Numbers whose digit product equals the number of their digits. 1
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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 22 12:23 EDT 2019. Contains 321421 sequences. (Running on oeis4.)