0,2

Numbers n whose binary representation is 100, n times.

a(n)=8*a(n-1)+4 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 31 2009]

a(3)=292 because 292 translated in base 2 is three times 100: 100100100.

Octal...............decimal (comment from Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 14 2007):

0......................0

4......................4

44....................36

444..................292

4444................2340

44444..............18724

444444............149796

4444444..........1198372

44444444.........9586980

444444444.......76695844

4444444444.....613566756

etc. ...............etc.

For n=2, a(2)=8*0+4=4; n=3, a(3)=8*4+4=36; n=4, a(4)=8*36+4=292 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 31 2009]

Table[ FromDigits[ Flatten[ Table[{1, 0, 0}, {i, n}]], 2], {n, 0, 19}] (from Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 01 2005)

s=0; lst={s}; Do[s+=2^n; AppendTo[lst, s], {n, 2, 5!, 3}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 07 2008]

(PARI) a(n)=if(n<0, 0, (8^n-1)*4/7) (Michael Somos)

Sequence in context: A144889 A098916 A059416 this_sequence A093186 A000765 A026334

Adjacent sequences: A108016 A108017 A108018 this_sequence A108020 A108021 A108022

easy,nonn,new

Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), May 31 2005

More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 01 2005

simplify! [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 07 2008]