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!)
A036337 Largest integer with n digits and exactly n prime factors (counted with multiplicity). 3
7, 95, 994, 9999, 99996, 999992, 9999968, 99999840, 999999968, 9999999900, 99999999840, 999999999744, 9999999998720, 99999999998400, 999999999999000, 9999999999999744, 99999999999995904, 999999999999967232, 9999999999999989760, 99999999999999995904 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If all prime factors are distinct then a(n) >= A002110(n) which might give a contradiction for large enough n and so some primes have a multiplicity > k for some nonnegative k. - David A. Corneth, Oct 30 2018

LINKS

Table of n, a(n) for n=1..20.

C. Rivera, Composed primes (a related puzzle).

EXAMPLE

95 = 5 * 19, while 96, 97, 98, 99 and 100 have, respectively, 6,1,3,3 and 4 prime factors; thus 95 is the largest two digit number with exactly two prime factors.

PROG

(PARI) a(n) = forstep(i = 10^n-1, 10^(n-1), -1, if(bigomega(i) == n, return(i))) \\ David A. Corneth, Oct 30 2018

CROSSREFS

Cf. A002110, A036335, A036336, A036338.

Sequence in context: A015225 A183521 A342109 * A186378 A244856 A201990

Adjacent sequences:  A036334 A036335 A036336 * A036338 A036339 A036340

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Dec 15 1998

EXTENSIONS

More terms and better description from Matthew Conroy, May 25 2001

a(19) and a(20) from Zak Seidov, Oct 30 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 April 15 01:24 EDT 2021. Contains 342974 sequences. (Running on oeis4.)