A201462 Numbers that are not coprime to their 9's complement.

3, 6, 9, 11, 12, 15, 18, 21, 22, 24, 27, 30, 33, 36, 39, 42, 44, 45, 48, 51, 54, 55, 57, 60, 63, 66, 69, 72, 75, 77, 78, 81, 84, 87, 88, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 135, 138, 141, 144, 147, 148, 150, 153, 156, 159

Offset

1,1

Comments

All multiples of 3 are in this sequence. Multiples of 11 are in this sequence if they have an even number of digits or if they are also multiples of 3.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Example

22 is in the sequence because its 9's complement is 77 and gcd(22, 77) = 11 > 1.

Mathematica

(* First run the program for A061601 to define nineComplement *) Select[Range[200], GCD[#, nineComplement[#]] > 1 &]

Prog

(Magma) [n: n in [3..159] | Gcd(10^#Intseq(n)-1, n) gt 1]; // Bruno Berselli, Dec 02 2011
(Haskell)
a201462 n = a201462_list !! (n-1)
a201462_list = [x | x <- [1..], gcd x (a061601 x) > 1]
-- Reinhard Zumkeller, Dec 03 2011

Crossrefs

Cf. A061601 (9's complement of n), A192817 (complement).

Sequence in context: A153238 A343112 A230193 * A189302 A086883 A154777

Adjacent sequences: A201459 A201460 A201461 * A201463 A201464 A201465

Keyword

nonn,easy,base

Author

Alonso del Arte, Dec 01 2011

Status

approved