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A188650 Fixed points of A188649: numbers divisible by the reverse of all their divisors. 5
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 22, 33, 40, 44, 55, 66, 77, 88, 99, 101, 110, 121, 131, 151, 181, 191, 202, 220, 242, 262, 303, 313, 353, 363, 373, 383, 393, 404, 440, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
A188649(a(n)) = a(n);
A002385 and A046376 are subsequences; subsequence of A002113.
LINKS
PROG
(Haskell)
import Data.List (elemIndices)
a188650 n = a188650_list !! (n-1)
a188650_list =
map succ $ elemIndices 0 $ zipWith (-) [1..] $ map a188649 [1..]
(PARI) rev(n:int, B=10)=my(m=n%B); n\=B; while(n>0, m=m*B+n%B; n\=B); m
is(n)=fordiv(n, d, if(n%rev(d), return(0))); 1 \\ Charles R Greathouse IV, Jul 14 2011
(Python)
from math import lcm
from sympy import divisors
def ok(n): return n == lcm(*(int(str(d)[::-1]) for d in divisors(n)))
print([k for k in range(1, 10000) if ok(k)]) # Michael S. Branicky, Sep 30 2022
CROSSREFS
Sequence in context: A114801 A114802 A055933 * A132578 A101318 A337925
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Apr 11 2011
STATUS
approved

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Last modified July 12 23:07 EDT 2024. Contains 374257 sequences. (Running on oeis4.)