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A028348
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Numbers k such that k^2 + 3*k + 1 is a palindrome.
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1
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1, 2, 6, 10, 12, 21, 29, 35, 94, 100, 117, 122, 325, 380, 442, 1000, 1132, 1307, 3073, 10000, 10325, 10602, 12652, 13207, 30404, 30834, 31474, 32672, 95603, 96439, 100000, 110665, 234566, 236026, 308863, 709781, 987443, 1000000, 1060602, 1099265, 1172835
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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palQ[n_]:=Module[{id=IntegerDigits[n^2+3n+1]}, id==Reverse[id]]; Select[Range[240000], palQ] (* Harvey P. Dale, Apr 17 2012 *)
Select[Range[1173000], PalindromeQ[#^2+3#+1]&] (* Harvey P. Dale, Jun 09 2022 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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Extended and definition corrected by T. D. Noe, Apr 17 2012
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STATUS
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approved
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