A161732 Fixed points of the TITO operation (A161594) that are also composite palindromes.

4, 6, 8, 9, 22, 33, 44, 55, 66, 77, 88, 99, 121, 202, 242, 252, 262, 303, 343, 363, 393, 404, 484, 505, 525, 606, 616, 626, 686, 707, 808, 909, 939, 1111, 1331, 1441, 1661, 1991, 2112, 2222, 2662, 2772, 2882, 3333, 3443, 3773, 3883, 3993, 4224, 4444, 5445

Offset

1,1

Comments

This sequence is a proper superset of A046351 (palindromic composite numbers with only palindromic prime factors). The smallest number that doesn't belong to A046351 is 72927. The numbers that are in this sequence and are not in A046351 are given in A161730.

Links

Table of n, a(n) for n=1..51.

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[10000], f[ # ] == # && rev[ # ] == # && ! PrimeQ[ # ] &]

Crossrefs

Cf. A161594, A161597, A161598, A161600, A046351

Sequence in context: A032350 A078337 A046351 * A066307 A287198 A099071

Adjacent sequences: A161729 A161730 A161731 * A161733 A161734 A161735

Keyword

base,nonn

Author

Tanya Khovanova, Jun 17 2009

Extensions

Edited by N. J. A. Sloane, Jun 23 2009

Status

approved