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A167719 Squares that become a prime number when prefixed with a 4 1

%I #7 May 14 2022 16:38:23

%S 1,49,289,441,729,1521,1681,1849,2209,3481,3721,3969,5329,6889,7569,

%T 8281,8649,9409,9801,11449,13689,14641,17161,21609,25281,29241,29929,

%U 31329,36481,39601,47961,61009,67081,68121,69169,73441,88209,97969

%N Squares that become a prime number when prefixed with a 4

%H Harvey P. Dale, <a href="/A167719/b167719.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[1,811,2]^2,PrimeQ[FromDigits[Join[{4},IntegerDigits[#]]]]&] (* _Harvey P. Dale_, Oct 16 2011 *)

%K base,nonn

%O 1,2

%A _Claudio Meller_, Nov 10 2009

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Last modified June 18 08:27 EDT 2024. Contains 373472 sequences. (Running on oeis4.)