

A054214


Numbers n such that n concatenated with n1 is a square.


9



82, 8242, 9802, 538277, 998002, 77837026, 99980002, 7922547265, 8643251345, 9223797610, 9999800002, 106710893290, 453378226757, 491023832065, 945958034530, 999998000002, 11916002265170, 15790977390245, 24917378001937
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OFFSET

1,1


COMMENTS

Every term contains even number of digits.  Max Alekseyev, May 14 2007
If n=(10^m1)^2+1 where m is a positive integer then n is in the sequence. Because n has 2m digits and n concatenated with n1 is n*10^(2m)+(n1)=(10^(2m)10^m+1)^2. Take m=1 we get 82 the first such term.  Farideh Firoozbakht, Aug 22 2013


LINKS

Table of n, a(n) for n=1..19.


EXAMPLE

E.g. '8242' + '82421' gives 82428241 which is 9079^2.


CROSSREFS

Cf. A054215, A054216, A030465, A030466, A030467, A020339, A020340.
Sequence in context: A097841 A116123 A116142 * A093241 A280361 A280671
Adjacent sequences: A054211 A054212 A054213 * A054215 A054216 A054217


KEYWORD

nonn,base


AUTHOR

Patrick De Geest, Feb 15 2000


EXTENSIONS

More terms from Max Alekseyev, May 14 2007


STATUS

approved



