A080177 Non-palindromic primes which on subtracting their reversal give perfect squares.
43, 73, 2141, 2251, 4253, 4363, 4583, 6701, 7211, 7321, 7541, 8147, 8923, 9103, 9323, 9433, 40093, 40193, 40493, 40693, 40993, 80897, 102101, 105401, 106501, 108401, 109001, 112111, 114311, 118411, 121021, 124021, 127321, 135131, 135431, 136531
Offset: 1
Examples
a(2)=73 because 73-37=36 which is a perfect square.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
- Archimedes' Lab, What is special about this number? - 43.
Programs
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Mathematica
Select[Prime[Range[13000]],!PalindromeQ[#]&&IntegerQ[Sqrt[#-IntegerReverse[ #]]]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 03 2018 *)
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PARI
forprime(p=1, 19999, issquare(p-A004086(p))&&p-A004086(p)&&print1(p", ")) \\ - M. F. Hasler, Nov 20 2013
Comments