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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 (list; graph; refs; listen; history; text; internal format)
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

Chai Wah Wu, Table of n, a(n) for n = 1..2278

Erich Friedman, Problem of the Month (June 1999)

M. F. Hasler, Sum of palindromes, OEIS wiki, Sep 10 2015

Chai Wah Wu, Table of n, a(n) for n = 1..481384 (zipped file)

CROSSREFS

Cf. A002113, A261907, A261910, A261911, A261913, A262528.

Sequence in context: A043642 A122233 A122243 * A122236 A122246 A210895

Adjacent sequences:  A261909 A261910 A261911 * A261913 A261914 A261915

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

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Last modified September 29 04:22 EDT 2020. Contains 337420 sequences. (Running on oeis4.)