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A178664 2^n concatenated with itself. 4
11, 22, 44, 88, 1616, 3232, 6464, 128128, 256256, 512512, 10241024, 20482048, 40964096, 81928192, 1638416384, 3276832768, 6553665536, 131072131072, 262144262144, 524288524288, 10485761048576, 20971522097152, 41943044194304 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(1)=22 because 2^1 concatenated with 2^1 is 22.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

FORMULA

a(n) = A020338(2^n). - Bruno Berselli, Mar 14 2012

MATHEMATICA

Table[FromDigits[Join[IntegerDigits[2^n], IntegerDigits[2^n]]], {n, 0, 30}] (* Vincenzo Librandi, Mar 14 2012 *)

PROG

(MAGMA) [Seqint(Intseq(2^n) cat Intseq(2^n)): n in [0..40]]; // Vincenzo Librandi, Mar 14 2012

CROSSREFS

Cf. A000079.

Sequence in context: A242958 A005015 A070069 * A292926 A109687 A225361

Adjacent sequences:  A178661 A178662 A178663 * A178665 A178666 A178667

KEYWORD

nonn,easy,base

AUTHOR

Vincenzo Librandi, Jul 10 2010

STATUS

approved

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Last modified September 17 03:42 EDT 2021. Contains 347478 sequences. (Running on oeis4.)