login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A163662 A020988 written in base 2. 3
10, 1010, 101010, 10101010, 1010101010, 101010101010, 10101010101010, 1010101010101010, 101010101010101010, 10101010101010101010, 1010101010101010101010, 101010101010101010101010, 10101010101010101010101010, 1010101010101010101010101010 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The digits are n concatenated blocks of (10).

Smallest number having alternating bit sum -n. Cf. A065359. - Washington Bomfim, Jan 22 2011

LINKS

Table of n, a(n) for n=1..14.

FORMULA

a(n) = Sum_{k=1,...,n} 10^(2k-1).

a(n) = 100*a(n-1) + 10 = 101*a(n-1) - 100*a(n-2).

G.f.: 10*x/((100*x-1)*(x-1)).

MAPLE

A163662 := proc(n) add(10^(2*k-1), k=1..n) ; end: seq(A163662(n), n=1..30) ; # R. J. Mathar, Jul 08 2009

CROSSREFS

Sequence in context: A106456 A079214 A176067 * A080070 A080120 A274069

Adjacent sequences:  A163659 A163660 A163661 * A163663 A163664 A163665

KEYWORD

nonn,base,easy

AUTHOR

Jaroslav Krizek, Aug 02 2009

EXTENSIONS

Recurrences and g.f. added by R. J. Mathar, Jul 08 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 29 01:46 EDT 2017. Contains 288856 sequences.