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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A299438 a(n) is the smallest number k such that there does not exist k numbers in the range [1..n] whose product is equal to its sum or -1 if no such number exists. 2
2, 3, 4, 6, 6, 15, 15, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 80, 80, 80, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 112, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114, 114 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If a(n) > 0 for all n, then sequence is nondecreasing and a(n) > n.

For n >= 38, a(n) appears to follow the pattern: a(n) = k_m for k_{m-1} <= n < k_m, for a sequence of numbers {k_m} = {38, 114, 174, 444, 4354, ... }.

Conjecture: a(n) > 0 for all n.

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..450

EXAMPLE

a(1) > 1 since the product of the list (1) is the same as its product. a(1) = 2 since the product of the list (1,1) = 1 which is not the same as its sum (= 2).

a(2) > 2 since (2,2) has both product and sum equal to 2. Similarly a(3) > 3 since (1,2,3) has both sum and product equal to 6.

CROSSREFS

Cf. A299439.

Sequence in context: A002729 A135510 A265398 * A030209 A265399 A138588

Adjacent sequences:  A299435 A299436 A299437 * A299439 A299440 A299441

KEYWORD

nonn

AUTHOR

Chai Wah Wu, Feb 19 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 June 20 19:36 EDT 2019. Contains 324234 sequences. (Running on oeis4.)