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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
72927, 76167, 434434, 868868, 1226221, 4778774, 5703075, 8755578, 9386839, 13488431, 43877834, 123848321, 564414465, 777555777, 1072772701, 1946776491, 9935115399, 12467976421, 52854045825, 74663436647, 83361616338, 95829592859 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
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.
LINKS
M. F. Hasler, Table of n, a(n) for n = 1..35. [From M. F. Hasler, Jun 25 2009]
T. Khovanova, Turning Numbers Inside Out [From Tanya Khovanova, Jul 07 2009]
MATHEMATICA
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]] &]
PROG
(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
CROSSREFS
Sequence in context: A237555 A186047 A252333 * A071145 A254582 A254589
KEYWORD
base,nonn
AUTHOR
Tanya Khovanova, Jun 17 2009
EXTENSIONS
Edited by N. J. A. Sloane, Jun 23 2009
Terms beyond a(6) from M. F. Hasler, Jun 25 2009
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)