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

Author

Alonso del Arte, Dec 01 2011

Keywords

• nonn
• easy
• base

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.

Examples

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

Links

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

Crossrefs

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

Programs

Haskell

a201462 n = a201462_list !! (n-1)
a201462_list = [x | x <- [1..], gcd x (a061601 x) > 1]
-- Reinhard Zumkeller, Dec 03 2011

Magma

[n: n in [3..159] | Gcd(10^#Intseq(n)-1,n) gt 1]; // Bruno Berselli, Dec 02 2011

Mathematica

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