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A224848
Reverse concatenation of the square of first a(n) integers gives a prime.
0
2, 3, 14, 700, 2818
OFFSET
1,1
COMMENTS
The number corresponding to a(5) = 2818 is a probable prime of 18269 digits. - Giovanni Resta, Jul 25 2013
EXAMPLE
a(4) = 700 because reverse concatenation of squares of 1 to 700 gives 490000488601......2516941 which is a 3742-digit prime number.
CROSSREFS
Cf. A091314.
Sequence in context: A101003 A042071 A042817 * A271330 A262462 A180698
KEYWORD
nonn,hard,more,base
AUTHOR
Shyam Sunder Gupta, Jul 22 2013
EXTENSIONS
a(5) from Giovanni Resta, Jul 25 2013
STATUS
approved