

A072135


Least m such that sqrt(m) has a period 2n continued fraction expansion whose palindrome part concatenates to a palindromic prime.


1



23, 22, 234, 115, 1208, 212, 1269, 999, 7370, 5019, 3087, 244, 2329, 2171, 147112, 90155, 165407, 7939, 57451, 69224, 62064, 19503, 19844, 563298, 265095, 14759823, 121726, 167817, 97100, 808386, 7353035, 1231680, 201722, 4754844, 91904459
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OFFSET

2,1


LINKS

Table of n, a(n) for n=2..36.
Jon E. Schoenfield, The continued fraction for each term up through a(49)


EXAMPLE

23 is in the sequence because it is the first followed by 47, 96, 98, 119, 128, ... all exhibiting the following property:sqrt(23) = [4;1, 3, 1, 8], sqrt(47) = [6;1, 5, 1, 12], sqrt(96) = [9;1, 3, 1, 18], sqrt(98) = [9;1, 8, 1, 18], sqrt(119) = [10;1, 9, 1, 20], sqrt(128) = [11;3, 5, 3, 22], ... i.e. the continued fraction expansion of their square roots have palindrome parts which concatenate respectively to the 3digit palprimes 131, 151, 131, 181, 191, 353, ...


CROSSREFS

Sequence in context: A004464 A255228 A255221 * A204633 A010862 A291570
Adjacent sequences: A072132 A072133 A072134 * A072136 A072137 A072138


KEYWORD

hard,nice,nonn,base


AUTHOR

Lekraj Beedassy, Jun 26 2002


EXTENSIONS

a(5)a(36) from Jon E. Schoenfield, Apr 02 2010


STATUS

approved



