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A138144 Palindromes formed from the reflected decimal expansion of the concatenation of 1, 1 and infinite 0's. 12
1, 11, 111, 1111, 11011, 110011, 1100011, 11000011, 110000011, 1100000011, 11000000011, 110000000011, 1100000000011, 11000000000011, 110000000000011, 1100000000000011, 11000000000000011, 110000000000000011 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(n) is also A147595(n) written in base 2. [From Omar E. Pol, Nov 08 2008]
LINKS
FORMULA
a(n) = 11+11*10^(n-2) for n>3. a(n) = 11*a(n-1)-10*a(n-2). G.f.: -x*(10*x^2-1)*(10*x^2+1) / ((x-1)*(10*x-1)). - Colin Barker, Sep 15 2013
EXAMPLE
n .... a(n)
1 .... 1
2 .... 11
3 .... 111
4 .... 1111
5 .... 11011
6 .... 110011
7 .... 1100011
8 .... 11000011
9 .... 110000011
10 ... 1100000011
MATHEMATICA
LinearRecurrence[{11, -10}, {1, 11, 111, 1111, 11011}, 20] (* Harvey P. Dale, Aug 21 2016 *)
PROG
(PARI) Vec(-x*(10*x^2-1)*(10*x^2+1)/((x-1)*(10*x-1)) + O(x^100)) \\ Colin Barker, Sep 15 2013
CROSSREFS
Cf. A000533.
Sequence in context: A283850 A283605 A083440 * A284243 A283005 A283256
KEYWORD
easy,nonn,base
AUTHOR
Omar E. Pol, Mar 29 2008
EXTENSIONS
Better definition. - Omar E. Pol, Nov 15 2008
STATUS
approved

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Last modified June 16 08:45 EDT 2024. Contains 373424 sequences. (Running on oeis4.)