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A188650 Fixed points of A188649: numbers divisible by the reverse of all their divisors.

%I A188650 #10 Sep 30 2022 09:26:07
%S A188650 1,2,3,4,5,6,7,8,9,10,11,20,22,33,40,44,55,66,77,88,99,101,110,121,
%T A188650 131,151,181,191,202,220,242,262,303,313,353,363,373,383,393,404,440,
%U A188650 484,505,606,626,707,727,757,787,797,808,909,919,929,939,1010,1111,1331,1441,1661,1991,2020,2222,2662,2882,3333,3443,3883,3993,4040,4444,5555,6666,6886,7777,7997,8888
%N A188650 Fixed points of A188649: numbers divisible by the reverse of all their divisors.
%C A188650 A188649(a(n)) = a(n);
%C A188650 A002385 and A046376 are subsequences; subsequence of A002113.
%H A188650 Michael S. Branicky, <a href="/A188650/b188650.txt">Table of n, a(n) for n = 1..10700</a>
%o A188650 (Haskell)
%o A188650 import Data.List (elemIndices)
%o A188650 a188650 n = a188650_list !! (n-1)
%o A188650 a188650_list =
%o A188650    map succ $ elemIndices 0 $ zipWith (-) [1..] $ map a188649 [1..]
%o A188650 (PARI) rev(n:int,B=10)=my(m=n%B);n\=B;while(n>0,m=m*B+n%B;n\=B);m
%o A188650 is(n)=fordiv(n,d,if(n%rev(d),return(0)));1 \\ _Charles R Greathouse IV_, Jul 14 2011
%o A188650 (Python)
%o A188650 from math import lcm
%o A188650 from sympy import divisors
%o A188650 def ok(n): return n == lcm(*(int(str(d)[::-1]) for d in divisors(n)))
%o A188650 print([k for k in range(1, 10000) if ok(k)]) # _Michael S. Branicky_, Sep 30 2022
%K A188650 nonn,base
%O A188650 1,2
%A A188650 _Reinhard Zumkeller_, Apr 11 2011