cp's OEIS Frontend

A178836 Numbers n such that the period of 1/n equals the period of 1/R(n), where R(n) (A004086) is the reversal of n.

%I A178836 #4 Mar 30 2012 18:35:53
%S A178836 3,7,9,11,33,77,99,101,111,121,131,141,151,161,171,181,191,303,313,
%T A178836 323,333,343,353,363,373,383,393,707,717,727,737,747,757,767,777,787,
%U A178836 797,909,919,929,939,949,959,969,979,989,999,1001,1111,1221,1331,1441,1551
%N A178836 Numbers n such that the period of 1/n equals the period of 1/R(n), where R(n) (A004086) is the reversal of n.
%C A178836 Non-palindromic numbers are included in this sequence :
%C A178836 {3267, 3927, 7293, 7632,...}
%e A178836 3267 is in the sequence because period (1/3267) = 66 and also period(1/7623) = 66.
%e A178836 3927 is in the sequence because period (1/3927) = 48 and also period(1/7293) = 48.
%p A178836 with(numtheory): nn:=8000:for n from 3 to nn do: s:=0:l:=length(n):for q from 0 to l-1 do:x:=iquo(n,10^q):y:=irem(x,10):s:=s+y*10^(l-1-q): od: indic1:=0:for p from 1 to nn do:if irem(10^p, n) = 1 and gcd(n, 5) = 1 and indic1=0 then pp:=p: indic1:=1:else fi:od: indic2:=0:for p from 1 to nn do:if irem(10^p, s) = 1 and gcd(s, 5) = 1 and indic2=0 then ppp:=p:indic2:=1:else fi:od: if pp=ppp and indic1=1 and indic2=1 then print(n):else fi:od:
%Y A178836 Cf. A004086, A045572, A002329.
%K A178836 nonn,base
%O A178836 1,1
%A A178836 _Michel Lagneau_, Jun 16 2010