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A085306 Prime numbers such that first reversing digits and after squaring equals the result of first-squaring and after-reversing. Primes in A085305. 3
2, 3, 11, 13, 31, 101, 103, 113, 211, 311, 1013, 1021, 1031, 1103, 1201, 1301, 2011, 2111, 3001, 3011, 10103, 10111, 10211, 11003, 11113, 12011, 12101, 13001, 20011, 20021, 20101, 20201, 21001, 21011, 21101, 22111, 30011, 100003, 100103, 101021 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000

FORMULA

Prime number solutions to rev(x^2) = rev(x)^2.

EXAMPLE

n=13 is here because 31^2 = 961 = rev(169) = rev(13^2) = rev(rev(31)^2).

65 solutions below 1000000.

MATHEMATICA

rt[x_] := tn[Reverse[IntegerDigits[x]]] Do[s=rt[n^2]; s1=rt[n]^2; If[Equal[s, s1]&& !Equal[Mod[n, 10], 0]&&PrimeQ[n], Print[n]], {n, 1, 1000000}]

CROSSREFS

Cf. A085305.

Sequence in context: A157884 A234530 A235632 * A161322 A123239 A048891

Adjacent sequences:  A085303 A085304 A085305 * A085307 A085308 A085309

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Jun 27 2003

STATUS

approved

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Last modified September 26 15:27 EDT 2017. Contains 292531 sequences.