

A091680


Smallest number whose base4 Reverse and Add! trajectory (presumably) contains exactly n base4 palindromes, or 1 if there is no such number.


2



290, 78, 18, 6, 3, 36, 21, 19, 7, 8, 4, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1
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OFFSET

0,1


COMMENTS

Conjecture 1: For each k > 0 the trajectory of k eventually leads to a term in the trajectory of some j which belongs to A075421, i.e., whose trajectory (presumably) never leads to a palindrome. Conjecture 2: There is no k > 0 such that the trajectory of k contains more than twelve palindromes, i.e., a(n) = 1 for n > 12.
Base4 analog of A077594.


LINKS

Table of n, a(n) for n=0..20.
Index entries for sequences related to Reverse and Add!


EXAMPLE

a(4) = 3 since the trajectory of 3 contains the four palindromes 3, 15, 975, 64575 (3, 33, 33033, 3330333 in base 4) and at 20966400 joins the trajectory of 318 = A075421(2) and the trajectories of 1 (A035524) and 2 do not contain exactly four palindromes.


CROSSREFS

Cf. A075299, A035524, A014192, A075420, A075421, A077594.
Sequence in context: A013761 A013883 A180701 * A129245 A186553 A075420
Adjacent sequences: A091677 A091678 A091679 * A091681 A091682 A091683


KEYWORD

base,sign


AUTHOR

Klaus Brockhaus, Jan 28 2004


STATUS

approved



