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A028413 Numbers k such that k^2 + k + 1 is a palindrome. 3

%I

%S 0,1,2,10,18,27,100,125,173,1000,1120,1184,1355,1836,1876,1961,10000,

%T 11915,100000,119084,126935,187876,188348,192383,196813,1000000,

%U 1010200,1190915,1228425,1780728,1821636,1975356,10000000,11842184,12643549,12783239,18016058

%N Numbers k such that k^2 + k + 1 is a palindrome.

%H Giovanni Resta, <a href="/A028413/b028413.txt">Table of n, a(n) for n = 1..68</a>

%H P. De Geest, <a href="http://www.worldofnumbers.com/quasisq.htm">Palindromic quasi_over_squares of the form n^2+(n+1)</a>

%t palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 1; Select[Range[0, 10^5], palQ@ f@ # &] (* _Giovanni Resta_, Aug 29 2018 *)

%Y Cf. A002113, A028414, A028336, A027712.

%K nonn,base

%O 1,3

%A _Patrick De Geest_

%E More terms from _Giovanni Resta_, Aug 28 2018

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Last modified June 24 18:46 EDT 2021. Contains 345419 sequences. (Running on oeis4.)