|
%I #21 Mar 20 2023 13:46:41
%S 3,6,9,11,12,15,18,21,22,24,27,30,33,36,39,42,44,45,48,51,54,55,57,60,
%T 63,66,69,72,75,77,78,81,84,87,88,90,93,96,99,102,105,108,111,114,117,
%U 120,123,126,129,132,135,138,141,144,147,148,150,153,156,159
%N Numbers that are not coprime to their 9's complement.
%C 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.
%H Reinhard Zumkeller, <a href="/A201462/b201462.txt">Table of n, a(n) for n = 1..10000</a>
%e 22 is in the sequence because its 9's complement is 77 and gcd(22, 77) = 11 > 1.
%t (* First run the program for A061601 to define nineComplement *) Select[Range[200], GCD[#, nineComplement[#]] > 1 &]
%o (Magma) [n: n in [3..159] | Gcd(10^#Intseq(n)-1,n) gt 1]; // _Bruno Berselli_, Dec 02 2011
%o (Haskell)
%o a201462 n = a201462_list !! (n-1)
%o a201462_list = [x | x <- [1..], gcd x (a061601 x) > 1]
%o -- _Reinhard Zumkeller_, Dec 03 2011
%Y Cf. A061601 (9's complement of n), A192817 (complement).
%K nonn,easy,base
%O 1,1
%A _Alonso del Arte_, Dec 01 2011
|
