|
| |
|
|
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
|
Cf. 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
|
| |
|
|
