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A224848 Reverse concatenation of the square of first a(n) integers gives a prime. 0
2, 3, 14, 700, 2818 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The number corresponding to a(5) = 2818 is a probable prime of 18269 digits. - Giovanni Resta, Jul 25 2013

The number corresponding to a(5) = 2818 is prime (definite, not probable), according to Wolfram Mathematica 11.0 and Maple 2018. - Kellen Myers, Dec 04 2019

LINKS

Table of n, a(n) for n=1..5.

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

Adjacent sequences:  A224845 A224846 A224847 * A224849 A224850 A224851

KEYWORD

nonn,hard,more,base

AUTHOR

Shyam Sunder Gupta, Jul 22 2013

EXTENSIONS

a(5) from Giovanni Resta, Jul 25 2013

STATUS

approved

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Last modified September 27 12:30 EDT 2020. Contains 337380 sequences. (Running on oeis4.)