login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A327786 Numbers whose number of distinct prime factors is greater than the sum of their digits. 1
10, 100, 110, 210, 1000, 1001, 1010, 1020, 1100, 1110, 2010, 2100, 10000, 10010, 10020, 10100, 10101, 10110, 10200, 11000, 11010, 11100, 20010, 20020, 20100, 21000, 100000, 100002, 100010, 100011, 100020, 100100, 100110, 100200, 101000, 101010, 101100, 102000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence is infinite since every number of the form 10^k for k >= 1 is in the sequence. It can be proved that 210 is the largest term with distinct digits.

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 291 terms from Metin Sariyar)

EXAMPLE

For a(4) = 210, 2 + 1 + 0 = 3, 210 = 2*3*5*7 with 4 distinct factors, 4 > 3 so 210 is a term.

MATHEMATICA

Select[Range[10^6], Total[IntegerDigits[#]]<Length[FactorInteger[#]]&]

PROG

(PARI) isok(n) = omega(n) > sumdigits(n); \\ Michel Marcus, Sep 25 2019

(MAGMA) [k:k in [2..110000]| #PrimeDivisors(k) gt &+Intseq(k)]; // Marius A. Burtea, Oct 07 2019

CROSSREFS

Cf. A001221, A165256.

Sequence in context: A169662 A124252 A121030 * A154810 A099820 A273245

Adjacent sequences:  A327783 A327784 A327785 * A327787 A327788 A327789

KEYWORD

nonn,base

AUTHOR

Metin Sariyar, Sep 25 2019

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 July 5 20:21 EDT 2020. Contains 335473 sequences. (Running on oeis4.)