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Numbers k such that k^2+k+5 is a palindrome.
4

%I #11 Aug 29 2018 16:56:58

%S 0,1,2,8,12,26,74,127,224,230,2751,3462,4012,4067,12752,22424,27548,

%T 28168,105322,107422,2358150,2724718,2775383,4063892,7569245,85125933,

%U 87579753,106617617,2237334999,2426472519,2765569146,2781875716,2815069131,4029203527

%N Numbers k such that k^2+k+5 is a palindrome.

%H Giovanni Resta, <a href="/A027718/b027718.txt">Table of n, a(n) for n = 1..46</a>

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

%Y Cf. A027728, A027690, A027754, A027755, A027716, A027729.

%K nonn,base

%O 1,3

%A _Patrick De Geest_

%E More terms from _Giovanni Resta_, Aug 28 2018