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A161730 Palindromic numbers that are fixed points of the TITO operation (see A161594) and are not products of palindromic primes. 3

%I

%S 72927,76167,434434,868868,1226221,4778774,5703075,8755578,9386839,

%T 13488431,43877834,123848321,564414465,777555777,1072772701,

%U 1946776491,9935115399,12467976421,52854045825,74663436647,83361616338,95829592859

%N Palindromic numbers that are fixed points of the TITO operation (see A161594) and are not products of palindromic primes.

%C The numbers in this sequence are palindromic numbers that are fixed points of the TITO operation and are not primes and are not in A046351.

%H M. F. Hasler, <a href="/A161730/b161730.txt">Table of n, a(n) for n = 1..35</a>. [From _M. F. Hasler_, Jun 25 2009]

%H T. Khovanova, <a href="http://blog.tanyakhovanova.com/?p=144">Turning Numbers Inside Out</a> [From _Tanya Khovanova_, Jul 07 2009]

%t reversepower[{n_, k_}] := FromDigits[Reverse[IntegerDigits[n]]]^k f[n_] := FromDigits[ Reverse[IntegerDigits[Times @@ Map[reversepower, FactorInteger[n]]]]] rev[n_] := FromDigits[Reverse[IntegerDigits[n]]] Select[Range[5000000], rev[ # ] == # && ! PrimeQ[ # ] && f[ # ] == # && Map[rev, Transpose[FactorInteger[ # ]][[1]]] != Transpose[FactorInteger[ # ]][[1]] &]

%o (PARI) for( d=1,19, my(p=10^((d+1)\2),q=10^(d%2)); for( i=p\10,p-1, my(n = i\q*p+R(i),f); A161594(n)==n || next; apply(R,f=factor(n)[,1])==f && next; print1(n",") )) /* uses definitions given in A161594 */ \\ _M. F. Hasler_, Jun 25 2009

%Y Cf. A161594, A161597, A161598, A161600.

%K base,nonn

%O 1,1

%A _Tanya Khovanova_, Jun 17 2009

%E Edited by _N. J. A. Sloane_, Jun 23 2009

%E Terms beyond a(6) from _M. F. Hasler_, Jun 25 2009

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Last modified April 20 11:50 EDT 2021. Contains 343135 sequences. (Running on oeis4.)