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A127906 a(n) = (n in base 10) * (n in base 2). 3
0, 1, 20, 33, 400, 505, 660, 777, 8000, 9009, 10100, 11121, 13200, 14313, 15540, 16665, 160000, 170017, 180180, 190209, 202000, 212121, 222420, 232553, 264000, 275025, 286260, 297297, 310800, 321929, 333300, 344441, 3200000, 3300033, 3400340, 3500385 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n) is a square for n=0 or a power of 4 (A000302). - Michel Marcus, Feb 20 2016

a(n) is a palindrome for n=0, 1, 3, 5, 7, 9, 33, 313, 455, 585, 819. Question: What is the next such n? If it exists it is greater than 10^9. - Michel Marcus, Feb 20 2016

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = n*A007088(n). - Michel Marcus, Feb 21 2016

EXAMPLE

0*0, 1*1, 2*10, 3*11, 4*100, 5*101, 6*110, 7*111, 8*1000, 9*1001, 10*1010, ...

a(14) is 14*1110 = 15540.

MAPLE

A007088:= proc(n) option remember;

   (n mod 2) + 10 * procname(floor(n/2))

end proc:

A007088(0):= 0:

seq(n*A007088(n), n=0..100); # Robert Israel, Feb 21 2016

MATHEMATICA

Table[n*FromDigits[IntegerDigits[n, 2]], {n, 0, 30}] (* Stefan Steinerberger, May 05 2007 *)

PROG

(PARI) a(n) = n*subst(Pol(binary(n)), x, 10) ; \\ Michel Marcus, Feb 20 2016

(MAGMA) [Seqint(Intseq((n), 2))*n: n in [0..50]]; // Vincenzo Librandi, Feb 20 2016

CROSSREFS

Cf. A007088.

Sequence in context: A075230 A165236 A067468 * A108667 A108669 A293694

Adjacent sequences:  A127903 A127904 A127905 * A127907 A127908 A127909

KEYWORD

nonn,base

AUTHOR

Ivan Baroni (estatico04(AT)yahoo.com.br), Apr 05 2007

EXTENSIONS

Corrected and extended by Stefan Steinerberger, May 05 2007

Offset set to 0 by Michel Marcus, Feb 20 2016

STATUS

approved

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Last modified April 21 19:16 EDT 2021. Contains 343156 sequences. (Running on oeis4.)