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

 

Logo

Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A171797 a(n) = concatenation of (number of digits in n) (number of even digits) (number of odd digits). 2
101, 110, 101, 110, 101, 110, 101, 110, 101, 211, 202, 211, 202, 211, 202, 211, 202, 211, 202, 220, 211, 220, 211, 220, 211, 220, 211, 220, 211, 211, 202, 211, 202, 211, 202, 211, 202, 211, 202, 220, 211, 220, 211, 220, 211, 220, 211, 220, 211, 211, 202 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Start with n, repeatedly apply the map i -> a(i). Then every number converges to 312. - Eric Angelini and Alexandre Wajnberg, Oct 15 2010.

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..25000 [From Reinhard Zumkeller, Oct 16 2010]

EXAMPLE

11 has 2 digits, both odd, so a(11)=202.

12 has 2 digits, one even and one odd, so a(12)=211. Then a(211) = 312.

MAPLE

Contribution from R. J. Mathar, Oct 15 2010: (Start)

nevenDgs := proc(n) local a; a := 0 ; for d in convert(n, base, 10) do if type(d, 'even') then a :=a +1 ; end if; end do; a ; end proc:

catL := proc(L) local a; a := op(1, L) ; for i from 2 to nops(L) do a := cat2(a, op(i, L)) ; end do; a; end proc:

A055642 := proc(n) max(1, ilog10(n)+1) ; end proc:

A171797 := proc(n) local n1, n2 ; n1 := A055642(n) ; n2 := nevenDgs(n) ; catL([n1, n2, n1-n2]) ; end proc:

seq(A171797(n), n=1..80) ; (End)

PROG

(Haskell)

a171797 n = read $ concatMap (show . ($ n))

                   [a055642, a196563, a196564] :: Integer

-- Reinhard Zumkeller, Feb 22 2012, Oct 15 2010

CROSSREFS

Cf. A171798, A171813.

Cf. A055642, A196563, A196564.

Sequence in context: A092628 A107219 A140799 * A025349 A025341 A086918

Adjacent sequences:  A171794 A171795 A171796 * A171798 A171799 A171800

KEYWORD

nonn,base,easy,look

AUTHOR

N. J. A. Sloane, Oct 15 2010

EXTENSIONS

More terms from R. J. Mathar, Oct 15 2010

Adapted function names in the maple program - R. J. Mathar, Oct 18 2010

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified July 31 23:43 EDT 2014. Contains 245090 sequences.