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A171797
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a(n) = concatenation of (number of digits in n) (number of even digits) (number of odd digits).
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2
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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
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OFFSET
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1,1
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COMMENTS
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Start with n, repeatedly apply the map i -> a(i). Then every number converges to 312. - Eric Angelini and Alexandre Wajnberg, Oct 15 2010.
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LINKS
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R. Zumkeller, Table of n, a(n) for n = 1..25000 [From Reinhard Zumkeller, Oct 16 2010]
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EXAMPLE
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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.
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MAPLE
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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)
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PROG
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(Haskell)
a171797 n = read $ concatMap (show . ($ n))
[a055642, a196563, a196564] :: Integer
-- Reinhard Zumkeller, Feb 22 2012, Oct 15 2010
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CROSSREFS
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Cf. A171798, A171813.
Cf. A055642, A196563, A196564.
Sequence in context: A092628 A107219 A140799 * A025349 A025341 A086918
Adjacent sequences: A171794 A171795 A171796 * A171798 A171799 A171800
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KEYWORD
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nonn,base,easy
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AUTHOR
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N. J. A. Sloane, Oct 15 2010
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EXTENSIONS
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More terms from R. J. Mathar, Oct 15 2010
Adapted function names in the maple program - R. J. Mathar, Oct 18 2010
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STATUS
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approved
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