cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A085306 Prime numbers such that first reversing digits and after squaring equals the result of first-squaring and after-reversing. Primes in A085305.

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%I A085306 #12 Feb 13 2021 14:02:42
%S A085306 2,3,11,13,31,101,103,113,211,311,1013,1021,1031,1103,1201,1301,2011,
%T A085306 2111,3001,3011,10103,10111,10211,11003,11113,12011,12101,13001,20011,
%U A085306 20021,20101,20201,21001,21011,21101,22111,30011,100003,100103,101021
%N A085306 Prime numbers such that first reversing digits and after squaring equals the result of first-squaring and after-reversing. Primes in A085305.
%H A085306 Donovan Johnson, <a href="/A085306/b085306.txt">Table of n, a(n) for n = 1..1000</a>
%F A085306 Prime number solutions to rev(x^2) = rev(x)^2.
%e A085306 n=13 is here because 31^2 = 961 = rev(169) = rev(13^2) = rev(rev(31)^2).
%e A085306 65 solutions below 1000000.
%t A085306 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}]
%t A085306 (* Second program: *)
%t A085306 Select[Prime[Range[10^5]], IntegerReverse[#]^2 == IntegerReverse[#^2]&] (* _Jean-François Alcover_, Feb 13 2021 *)
%Y A085306 Cf. A085305.
%K A085306 base,nonn
%O A085306 1,1
%A A085306 _Labos Elemer_, Jun 27 2003