All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Even Digit Perfect Square(s) (Posted on 2008-10-25) Difficulty: 3 of 5
Determine all possible 7-digit decimal (base 10) perfect square(s), each of whose digits is nonzero and even.

Note: While a solution is trivial with the aid of a computer program, show how to derive it without one.

See The Solution Submitted by K Sengupta    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution re: SLOANE A103705 (spoiler) | Comment 3 of 10 |
(In reply to SLOANE A103705 by Ady TZIDON)

1. Isn't it A030098? ... or A103751?

2. Now that a computer program is being used (IE, Firefox or Chrome), might as well do one tailored to the task instead:

st = INT(SQR(1000000)): fin = INT(SQR(9999999))
FOR sr = st TO fin
 sq = sr * sr
 s$ = LTRIM$(STR$(sq))
 good = 1
 FOR i = 1 TO LEN(s$)
   IF INSTR("2468", MID$(s$, i, 1)) = 0 THEN good = 0: EXIT FOR
 IF good THEN PRINT s$


I would be interested in how one could do this with no computer.

Edited on October 25, 2008, 5:10 pm

Edited on October 26, 2008, 1:56 am
  Posted by Charlie on 2008-10-25 17:05:34

Please log in:
Remember me:
Sign up! | Forgot password

Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (4)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Copyright © 2002 - 2018 by Animus Pactum Consulting. All rights reserved. Privacy Information