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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. 0
3, 7, 9, 11, 33, 77, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 707, 717, 727, 737, 747, 757, 767, 777, 787, 797, 909, 919, 929, 939, 949, 959, 969, 979, 989, 999, 1001, 1111, 1221, 1331, 1441, 1551 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Non-palindromic numbers are included in this sequence :

{3267, 3927, 7293, 7632,...}

LINKS

Table of n, a(n) for n=1..53.

EXAMPLE

3267 is in the sequence because period (1/3267) = 66 and also period(1/7623) = 66.

3927 is in the sequence because period (1/3927) = 48 and also period(1/7293) = 48.

MAPLE

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:

CROSSREFS

Cf. A004086, A045572, A002329.

Sequence in context: A191181 A046807 A333423 * A338712 A263926 A114788

Adjacent sequences:  A178833 A178834 A178835 * A178837 A178838 A178839

KEYWORD

nonn,base

AUTHOR

Michel Lagneau, Jun 16 2010

STATUS

approved

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Last modified July 2 18:27 EDT 2022. Contains 355029 sequences. (Running on oeis4.)