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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

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 * A259300 A025349 A025341

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 | 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 December 5 15:24 EST 2016. Contains 278770 sequences.