|
| |
|
|
A125520
|
|
a(n) = maximal difference between two distinct n-digit with property that when one of them is typed into a calculator and rotated 180 degrees, the other one is seen.
|
|
0
| |
|
|
3, 75, 825, 8835, 89235, 898335, 8992335, 89983335, 899923335, 8999833335, 89999233335, 899998333335, 8999992333335
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
FORMULA
| If n is greater than 2 and even, than a(n) is 8 followed by (n / 2) - 2 nines followed by another 8 followed by (n / 2) - 1 threes followed by 5. If n is greater than 2 and odd, than a(n) is 8 followed by (n / 2) - 1.5 nines followed by a 2 followed by (n / 2) - 1.5 threes followed by a 5.
|
|
|
EXAMPLE
| a(2) = 75. If someone types 91 into a calculator and rotates it 180 degrees, they will get 16. 91 - 16 = 75. It is easy to check that no larger differences can be obtained.
|
|
|
CROSSREFS
| Sequence in context: A121981 A093183 A189805 * A163131 A060869 A012491
Adjacent sequences: A125517 A125518 A125519 * A125521 A125522 A125523
|
|
|
KEYWORD
| base,nonn
|
|
|
AUTHOR
| Tanya Khovanova and Sergei Bernstein (tanyakh(AT)yahoo.com), Dec 29 2006
|
| |
|
|
