A127906 a(n) = (n in base 10) * (n in base 2).

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

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