|
Search: id:A044712
|
|
|
| A044712 |
|
Numbers n such that string 8,8 occurs in the base 9 representation of n but not of n+1. |
|
+0
3
|
|
| 80, 161, 242, 323, 404, 485, 566, 647, 728, 809, 890, 971, 1052, 1133, 1214, 1295, 1376, 1457, 1538, 1619, 1700, 1781, 1862, 1943, 2024, 2105, 2186, 2267, 2348, 2429, 2510, 2591, 2672, 2753, 2834, 2915, 2996, 3077, 3158
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
If A=[A157507] 81*n.^2-2*n (n>0, 79, 320, 723,.,. ,.,); Y=[A010734] 9 (9,9,9,.,..,); X=[A044712] 81*n-1 (n>0, 80, 161, 242, ,. .,), we have, for all terms, Pell's equation X^2-A*Y^2=1. Example: 80^2-79*9^2=1; 161^2-320*9^2=1; 242^2-723*9^2=1. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 13 2009]
|
|
LINKS
|
Tanya Khovanova, Non Recursions
|
|
FORMULA
|
a(n)=81*n-1 (n>0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 13 2009]
|
|
EXAMPLE
|
For n=1, a(1)=80; n=2, a(2)=161; n=3, a(3)=242 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 13 2009]
|
|
CROSSREFS
|
Cf. A157597, A010734 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 13 2009]
Sequence in context: A043486 A031496 A044331 this_sequence A044412 A044793 A157912
Adjacent sequences: A044709 A044710 A044711 this_sequence A044713 A044714 A044715
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
Clark Kimberling (ck6(AT)evansville.edu)
|
|
|
Search completed in 0.002 seconds
|
