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A261912
Numbers with palindromic order 5.
4
101073, 101082, 101100, 101155, 101199, 102192, 102299, 103275, 103293, 103366, 103399, 103502, 104332, 104342, 104352, 104362, 104372, 104382, 104392, 104499, 104602, 105432, 105442, 105452, 105462, 105472, 105482, 105492, 105493, 105544, 105577, 105599, 105702
OFFSET
1,1
COMMENTS
See A261913 for definition.
In the Friedman Problem of the Month page, there is a statement by John Hoffman which, if I have interpreted it correctly, asserts that this sequence has only a finite number of terms. However, Chai Wah Wu has extended the sequence out to 10^8, finding 481384 terms, the last one being a(481384) = 99998180. This sequence does not appear to be finite.
The first terms of this sequence are just beyond A109326(5). It can be expected that at least beyond A109326(6) = 1000101024 there will be examples where N-prevpal(N) and N-prevpal(prevpal(N)) are both of order 5; these numbers could be termed to be of order 6, and so on. - M. F. Hasler, Sep 13 2015
LINKS
CROSSREFS
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Sep 10 2015
EXTENSIONS
More terms from Chai Wah Wu, Sep 11 2015 and Sep 12 2015
STATUS
approved