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A061601 9's complement of n: a(n) = 10^d - 1 - n where d is the number of digits in n. If a is a digit in n replace it with 9 - a. 25
9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

A109002 and A178500 give record values and where they occur: A109002(n+1)=a(A178500(n)) and a(m)<A109002(n+1) for m<A178500(n). [Reinhard Zumkeller, May 28 2010]

If n is divisible by 3, so is a(n). The same goes for 9. - Alonso del Arte, Dec 01 2011

REFERENCES

Kjartan Poskitt, Murderous Maths: Numbers, The Key to the Universe, Scholastic Ltd, 2002. See p 159.

LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..25000 (terms 0,...,1000 from Harry J. Smith)

FORMULA

a(n) = if n<10 then 9 - n else 10*a([n/10]) + 9 - n mod 10. [Reinhard Zumkeller, Jan 20 2010]

EXAMPLE

a(7) = 2 = 10 - 1 -7. a(123) = 1000 -1 -123 = 876.

MAPLE

A061601 := proc(n)

        10^A055642(n)-1-n ;

end proc: # R. J. Mathar, Nov 30 2011

MATHEMATICA

nineComplement[n_] := FromDigits[Table[9, {Length[IntegerDigits[n]]}] - IntegerDigits[n]]; Table[nineComplement[n], {n, 0, 71}] (* Alonso del Arte, Nov 30 2011 *)

PROG

(PARI) g(n) = for(x=0, n, ln=length(Str(x)); y=10^ln-1 - x; print1(y", ")) \\ Cino Hilliard, Mar 11 2006

(PARI) { for (n=0, 1000, ln=length(Str(n)); write("b061601.txt", n, " ", 10^ln - 1 - n) ) } \\ Harry J. Smith, Jul 25 2009

(PARI) A061601(n)={my(e=length(Str(n))); 10^e-1 - n; } \\ Joerg Arndt, Aug 28 2013

(Haskell)

a061601 n = if n <= 9 then 9 - n else 10 * ad n' + 9 - d

            where (n', d) = divMod n 10

-- Reinhard Zumkeller, Feb 21 2014, Oct 04 2011

(Python)

def A061601(n):

....return 10**len(str(n))-1-n # Indranil Ghosh, Jan 30 2017

CROSSREFS

Cf. A035327, A171960.

Cf. A055120.

See A267193 for complement obverse of n.

Sequence in context: A023451 A109910 A084019 * A098756 A267193 A112454

Adjacent sequences:  A061598 A061599 A061600 * A061602 A061603 A061604

KEYWORD

nonn,base,easy

AUTHOR

Amarnath Murthy, May 19 2001

EXTENSIONS

Corrected and extended by Matthew Conroy, Jan 19 2002

STATUS

approved

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Last modified November 16 21:40 EST 2018. Contains 317275 sequences. (Running on oeis4.)