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A206527 3^n concatenated with itself. 3
11, 33, 99, 2727, 8181, 243243, 729729, 21872187, 65616561, 1968319683, 5904959049, 177147177147, 531441531441, 15943231594323, 47829694782969, 1434890714348907, 4304672143046721, 129140163129140163, 387420489387420489 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

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

FORMULA

a(n) = A020338(3^n). - Bruno Berselli, Mar 14 2012

EXAMPLE

a(1)=33 because 3^1 concatenated with 3^1 is 33.

MATHEMATICA

Table[FromDigits[Join[IntegerDigits[3^n], IntegerDigits[3^n]]], {n, 0, 18}] (* Bruno Berselli, Mar 14 2012 *)

Table[3^n 10^IntegerLength[3^n]+3^n, {n, 0, 20}] (* Harvey P. Dale, May 27 2019 *)

PROG

(MAGMA) [Seqint(Intseq(3^n) cat Intseq(3^n)): n in [0..18]]; // Bruno Berselli, Mar 14 2012

CROSSREFS

Cf. A178664, A000244.

Sequence in context: A212132 A027025 A120354 * A297478 A213973 A262913

Adjacent sequences:  A206524 A206525 A206526 * A206528 A206529 A206530

KEYWORD

nonn,base,easy

AUTHOR

Vincenzo Librandi, Mar 14 2012

STATUS

approved

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Last modified September 27 18:56 EDT 2021. Contains 347694 sequences. (Running on oeis4.)