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A000461 Concatenate n n times. 22
1, 22, 333, 4444, 55555, 666666, 7777777, 88888888, 999999999, 10101010101010101010, 1111111111111111111111, 121212121212121212121212, 13131313131313131313131313, 1414141414141414141414141414 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A055642(a(n)) = n * A055642(n). [Reinhard Zumkeller, Apr 26 2011]

REFERENCES

F. Smarandache, "Properties of the numbers", Univ. of Craiova Archives, 1975; Arizona State University Special Collections, Tempe, AZ.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..333

Eric Weisstein's World of Mathematics, Smarandache Sequences

FORMULA

a(n) = n*(10^(n*L(n))-1)/(10^L(n)-1) where L(n) = A004216(n)+1 = floor(log_10(10n)). - Henry Bottomley, Jun 01 2000

a(n) = Sum_{i=0..n-1} (n*10^(i*(floor(log(10, n)) + 1))). - José de Jesús Camacho Medina, Dec 10 2014

MAPLE

a:= n-> parse(cat(n$n)):

seq(a(n), n=1..20);  # Alois P. Heinz, Apr 26 2011

MATHEMATICA

Table[Sum[(n)*10^(i*(Floor[Log[10, n]] + 1)), {i, 0, n - 1}], {n, 1, 30}] (* José de Jesús Camacho Medina, Dec 10 2014 *)

Table[FromDigits[Flatten[IntegerDigits/@Table[n, {n}]]], {n, 15}] (* Harvey P. Dale, Mar 01 2015 *)

Table[FromDigits[PadRight[{}, n IntegerLength[n], IntegerDigits[n]]], {n, 15}] (* Harvey P. Dale, Jun 19 2016 *)

PROG

(Haskell)

a000461 n = (read $ concat $ replicate n $ show n) :: Integer

-- Reinhard Zumkeller, Apr 26 2011

CROSSREFS

Cf. A048376, A053422.

Sequence in context: A158849 A048376 A053422 * A216730 A048795 A068186

Adjacent sequences:  A000458 A000459 A000460 * A000462 A000463 A000464

KEYWORD

nonn,base,easy

AUTHOR

John Radu (Suttones(AT)aol.com)

STATUS

approved

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Last modified March 27 08:32 EDT 2017. Contains 284146 sequences.