cp's OEIS Frontend

A243974 Integers n not of form 3m+1 such that for any integer k>0, n*10^k-1 has a divisor in the set { 7, 11, 13, 37 }.

%I A243974 #54 Apr 25 2016 11:50:02
%S A243974 10176,17601,19361,25827,27147,27686,35916,36048,45462,47213,48036,
%T A243974 49248,54638,62864,64184,64899,72953,73085,82499,85073,86285,93435,
%U A243974 101760,101936
%N A243974 Integers n not of form 3m+1 such that for any integer k>0, n*10^k-1 has a divisor in the set { 7, 11, 13, 37 }.
%C A243974 For n>24 a(n) = a(n-24) + 111111, the first 24 values are in the data.
%C A243974 If n is of form 3m+1 then n*10^k-1 is always divisible by 3. - _Jens Kruse Andersen_, Jul 09 2014
%F A243974 For n > 24, a(n) = a(n-24) + 111111.
%e A243974 10176*10^k-1 is divisible by 11 for k of form 6m, 6m+2, 6m+4, by 7 for k of form 6m+1, by 37 for 6m+3 (and also 6m), and by 13 for 6m+5. This covers all k. {7, 11, 13, 37} is called a covering set. - _Jens Kruse Andersen_, Jul 09 2014
%o A243974 (PFGW & SCRIPT)
%o A243974 SCRIPT
%o A243974 DIM k,0
%o A243974 DIM n
%o A243974 DIMS t
%o A243974 OPENFILEOUT myf,res.txt
%o A243974 LABEL loop1
%o A243974 SET k,k+1
%o A243974 SET n,0
%o A243974 LABEL loop2
%o A243974 SET n,n+1
%o A243974 IF n>500 THEN GOTO a
%o A243974 IF (k*10^n-1)%7==0 THEN GOTO loop2
%o A243974 IF (k*10^n-1)%11==0 THEN GOTO loop2
%o A243974 IF (k*10^n-1)%13==0 THEN GOTO loop2
%o A243974 IF (k*10^n-1)%37==0 THEN GOTO loop2
%o A243974 GOTO loop1
%o A243974 LABEL a
%o A243974 WRITE myf,k
%o A243974 PRINT k
%o A243974 GOTO loop1
%Y A243974 Cf. A076337, A243969, A243974, A244070, A244071, A244072, A244073, A244074, A244076.
%K A243974 nonn
%O A243974 1,1
%A A243974 _Pierre CAMI_, Jun 16 2014
%E A243974 Definition corrected by _Jens Kruse Andersen_, Jul 09 2014