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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A074312 Numbers k such that the product of the digits of k equals the number of divisors of k. 3
1, 2, 14, 22, 24, 32, 42, 116, 122, 126, 141, 211, 221, 222, 411, 512, 1114, 1118, 1128, 1132, 1141, 1144, 1218, 1222, 1242, 1314, 1332, 1411, 1611, 1612, 2111, 2114, 2132, 2214, 2232, 2312, 2511, 3114, 3211, 3212, 4116, 4131, 4312, 6112, 8211 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

EXAMPLE

24 is a term as the product of the digits of 24 is 2*4 = 8 and the number of divisors = 8.

MAPLE

with(numtheory):l := 1:a[1] := 1:for n from 2 to 10000 do d := convert(n, base, 10): if(product(d[i], i=1..nops(d))=tau(n)) then l := l+1:a[l] := n:fi:od:seq(a[i], i=1..l); # Sascha Kurz

MATHEMATICA

Select[Range[10^4], Apply[Times, IntegerDigits[ # ]] == DivisorSigma[0, # ] &]

CROSSREFS

Cf. A057531, A066613.

Sequence in context: A086263 A073143 A066613 * A061426 A190045 A247035

Adjacent sequences:  A074309 A074310 A074311 * A074313 A074314 A074315

KEYWORD

base,easy,nonn

AUTHOR

Joseph L. Pe, Sep 22 2002

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 October 23 07:11 EDT 2019. Contains 328336 sequences. (Running on oeis4.)