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A161600 Nonprime numbers such that TITO(n) = n, where TITO(n) = A161594(n). 8

%I #21 May 11 2015 19:25:00

%S 1,4,6,8,9,22,26,33,39,44,46,55,62,66,69,77,82,86,88,93,99,121,143,

%T 169,187,202,206,226,242,252,253,262,286,299,303,309,339,341,343,363,

%U 393,404,422,446,451,466,473,482,484,505,525,583,606,616,622,626,633,662,669,671,682,686

%N Nonprime numbers such that TITO(n) = n, where TITO(n) = A161594(n).

%H Reinhard Zumkeller, <a href="/A161600/b161600.txt">Table of n, a(n) for n = 1..10000</a>

%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]]]]]; Select[Range[600], f[#] == # && ! PrimeQ[#] &]

%o (Haskell)

%o a161600 n = a161600_list !! (n-1)

%o a161600_list = filter ((== 0) . a010051) a161597_list

%o -- _Reinhard Zumkeller_, Oct 14 2011

%o (PARI) is(n)=!isprime(n)&&n==A161594(n) \\ _M. F. Hasler_, May 11 2015

%Y Cf. A010051, A161594; subsequence of A161597.

%K nonn,base

%O 1,2

%A _J. H. Conway_ & _Tanya Khovanova_, Jun 14 2009

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

%E Offset corrected by _Reinhard Zumkeller_, Oct 14 2011

%E Minor edits and more displayed terms from _M. F. Hasler_, May 11 2015

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Last modified April 16 18:22 EDT 2024. Contains 371750 sequences. (Running on oeis4.)