

A218035


Number of ndigit palindromes with squares that are also palindromes.


0



4, 2, 5, 3, 8, 5, 13, 9, 22, 16, 37, 27, 60, 43, 93, 65, 138, 94
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OFFSET

1,1


COMMENTS

Number of ndigit terms in A057135.


LINKS

Table of n, a(n) for n=1..18.


FORMULA

Conjecture: a(n) = n^3/48  n^2/8 + 2n/3 + 1 if n even, see A011826.
Conjecture: a(n) = n^3/24  3n^2/8 + 59n/24  1/8 if n odd, n > 1.


EXAMPLE

For n=4, the solutions are:
1001, 1001^2 = 1002001,
1111, 1111^2 = 1234321,
2002, 2002^2 = 4008004.


CROSSREFS

Cf. A050683, A070252.
Sequence in context: A185511 A199855 A127914 * A090964 A219159 A213928
Adjacent sequences: A218032 A218033 A218034 * A218036 A218037 A218038


KEYWORD

nonn,base


AUTHOR

David Zvirbulis, Oct 19 2012


STATUS

approved



