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%I
%S 1,2,3,4,5,6,7,8,9,10,11,12,14,15,16,18,20,21,22,24,25,27,28,30,32,33,
%T 35,36,40,42,44,45,48,49,50,54,55,56,60,63,64,66,70,72,75,77,80,81,84,
%U 88,90,96,98,99,100,101,105,108,110,112,120,121,125,126,128,131
%N Numbers all of whose prime factors are palindromes.
%C Multiplicative closure of A002385; A051038 and A046368 are subsequences. [_Reinhard Zumkeller_, Apr 11 2011]
%o (Haskell)
%o a033620 n = a033620_list !! (n-1)
%o a033620_list = filter chi [1..] where
%o chi n = a136522 spf == 1 && (n' == 1 || chi n') where
%o n' = n `div` spf
%o spf = a020639 n -- cf. A020639
%o -- _Reinhard Zumkeller_, Apr 11 2011
%o (PARI) ispal(n)=n=digits(n);for(i=1,#n\2,if(n[i]!=n[#n+1-i],return(0)));1
%o is(n)=if(n<13,n>0,vecmin(apply(ispal,factor(n)[,1]))) \\ _Charles R Greathouse IV_, Feb 06 2013
%K nonn,base,easy
%O 1,2
%A _N. J. A. Sloane_, May 17 1998
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