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.

A207373 Numbers whose square is the product of a number and its reverse.

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%I A207373 #17 Apr 12 2019 06:52:50
%S A207373 252,403,504,660,816,2772,3267,4356,20502,22932,23632,25452,26962,
%T A207373 27972,31003,32967,35143,41004,43956,45864,48384,48616,55242,58422,
%U A207373 66976,75525,225522,252252,259952,279972,329967,341033,403403,439956,451044,504504,619916
%N A207373 Numbers whose square is the product of a number and its reverse.
%C A207373 Number and its reverse must have the same number of digits.
%C A207373 Number squared cannot be a palindrome. - _Harvey P. Dale_, Mar 12 2017
%H A207373 Giovanni Resta, <a href="/A207373/b207373.txt">Table of n, a(n) for n = 1..1169</a> (terms < 10^12, first 90 terms from Harvey P. Dale)
%e A207373 35143^2 = 96721*12769.
%t A207373 nir[n_]:=If[PalindromeQ[n]||Divisible[n,10],0,n IntegerReverse[n]]; Sqrt[#] &/@ Select[Array[nir,500000],#!=0&&IntegerQ[Sqrt[#]]&]//Union (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 12 2017 *)
%Y A207373 Cf. A076750.
%K A207373 nonn,base
%O A207373 1,1
%A A207373 _Carmine Suriano_, Feb 17 2012