mersenneforum.org 13x666=2020
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2020-11-26, 12:08   #23
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

579510 Posts

Quote:
 Originally Posted by petrw1 is SQRT(666*666) cheap?
Was trying to avoid that

 2020-11-26, 18:53 #24 swishzzz   Jan 2012 Toronto, Canada 5210 Posts (666 + (666+666+666)/666) * (13+13+13)/13 + 13 Uses 5 of each.
 2020-11-26, 20:26 #25 swishzzz   Jan 2012 Toronto, Canada 3416 Posts 13 * (13*13+13-666/(13+13)) - 13 8 numbers used.
2020-11-26, 20:58   #26
R. Gerbicz

"Robert Gerbicz"
Oct 2005
Hungary

59516 Posts

Quote:
 Originally Posted by petrw1 Find a formula using only 13 and 666 to get 2020. You can only use +. -, x, /, ^, !, √ 1. Find an answer with the fewest numbers (not digits). 2. Find an answer with the same number of each; and the fewest.
For Q2 the optimal is 9 terms (using 4 pieces of 13 and 5 pieces 666):
Code:
13-(666-(666+666)*(666+13*(13+13)))/666
and for Q1 the optimal is the above 8 terms.
Assuming that we would use "only" the +,-,*,/ operations (no other crazy . or concat) and no large (intermediate) numbers.

 2020-11-26, 21:29 #27 swishzzz   Jan 2012 Toronto, Canada 22·13 Posts I've proven by brute force search that there does not exist a solution using either 7 numbers or 4 of each, if we only allow the simple operators +, -, *, /. The closest solution with 4 of each is 13 + 13 + 666 + 666 + 666 - 666/(13*13) = 2020.05917...
 2020-11-26, 21:44 #28 swishzzz   Jan 2012 Toronto, Canada 22×13 Posts 2020 = 666 + 666 + 666 + sqrt(666 - 13*13 - 13) 7 numbers.
2020-11-26, 22:46   #29
VBCurtis

"Curtis"
Feb 2005
Riverside, CA

2×2,311 Posts

Quote:
 Originally Posted by swishzzz 2020 = 666 + 666 + 666 + sqrt(666 - 13*13 - 13) 7 numbers.
Genius!

2020-11-27, 12:21   #30
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

2·167 Posts

Quote:
 Originally Posted by swishzzz 2020 = 666 + 666 + 666 + sqrt(666 - 13*13 - 13) 7 numbers.
Nice!

2020-11-27, 14:00   #31
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

5·19·61 Posts

Quote:
 Originally Posted by swishzzz 2020 = 666 + 666 + 666 + sqrt(666 - 13*13 - 13) 7 numbers.
Very impressive

Note this can be converted to 4 of each quite easily:
2020 = 666 + 666 + 666 + sqrt(666 - 13*(13+13/13))

It would surprise me if these are beaten

2020-11-27, 16:19   #32
Ensigm

Aug 2020

2·3·19 Posts

Quote:
 Originally Posted by swishzzz 2020 = 666 + 666 + 666 + sqrt(666 - 13*13 - 13) 7 numbers.
Quote:
 Originally Posted by henryzz Note this can be converted to 4 of each quite easily: 2020 = 666 + 666 + 666 + sqrt(666 - 13*(13+13/13)) It would surprise me if these are beaten
I can only marvel at these.

2020-11-28, 11:23   #33
robert44444uk

Jun 2003
Oxford, UK

2·7·137 Posts

Quote:
 Originally Posted by henryzz Very impressive Note this can be converted to 4 of each quite easily: 2020 = 666 + 666 + 666 + sqrt(666 - 13*(13+13/13)) It would surprise me if these are beaten
Got to love it.

The newspapers need to be told - the World needs to know

I suggest the Daily Mail or the Sun in the UK, and Fox News for the telly. And the boys and girls in QAnon, and the anti Vaxxers, and the Covid deniers, and, and....

Last fiddled with by robert44444uk on 2020-11-28 at 11:23

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