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A246554 Concatenation of the n-th Fibonacci number with itself. 1
11, 11, 22, 33, 55, 88, 1313, 2121, 3434, 5555, 8989, 144144, 233233, 377377, 610610, 987987, 15971597, 25842584, 41814181, 67656765, 1094610946, 1771117711, 2865728657, 4636846368, 7502575025, 121393121393, 196418196418, 317811317811, 514229514229 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(n) is the n-th Fibonacci number concatenated with itself; concatenation A000045.
Also, the quotient of a(n) divided by the n-th Fibonacci number is 10^d(n)+1, where d(n) is the number of digits in the n-th Fibonacci number (A060384).
LINKS
FORMULA
a(n) = A000045(n)*(10^A060384(n)+1). - Robert Israel, Nov 16 2014
EXAMPLE
The 7th Fibonacci number, 13, is concatenated with itself to become a(7) = 1313.
MAPLE
A:= proc(n)
local f;
f:= combinat:-fibonacci(n);
(10^length(f)+1)*f;
end proc:
map(A, [$1..100]); # Robert Israel, Nov 16 2014
# second Maple program:
a:= n-> (p-> parse(cat(p$2)))((<<0|1>, <1|1>>^n)[1, 2]):
seq(a(n), n=1..100); # Alois P. Heinz, Nov 17 2014
MATHEMATICA
Table[FromDigits[Join[Flatten[IntegerDigits[{Fibonacci[n], Fibonacci[n]}]]]], {n, 50}] (* Vincenzo Librandi, Nov 15 2014 *)
#*10^IntegerLength[#]+#&/@Fibonacci[Range[30]] (* Harvey P. Dale, Jul 04 2015 *)
PROG
(PARI) a(n)=(k->eval(Str(k, k)))(fibonacci(n)) \\ Charles R Greathouse IV, Nov 15 2014
(Magma) [Seqint(Intseq(Fibonacci(n)) cat Intseq(Fibonacci(n))): n in [1..30]]; // Vincenzo Librandi, Nov 15 2014
CROSSREFS
Sequence in context: A003887 A138844 A022345 * A218163 A152082 A070849
KEYWORD
nonn,base
AUTHOR
Indrani Das, Nov 14 2014
STATUS
approved

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)