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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 */ [From M. F. Hasler, Jun 25 2009]

CROSSREFS

A161594, A161597, A161598, A161600

Sequence in context: A237555 A186047 A252333 * A071145 A254582 A254589

Adjacent sequences:  A161727 A161728 A161729 * A161731 A161732 A161733

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 September 26 15:27 EDT 2017. Contains 292531 sequences.