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A027722
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Numbers k such that k^2+k+7 is a palindrome.
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4
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0, 1, 17, 31, 177, 274, 280, 301, 313, 1777, 2764, 3001, 27259, 30001, 177237, 300001, 312208, 1762122, 3000001, 27515125, 30000001, 30122098, 300000001, 303758458, 2673533185, 2817818390, 3000000001, 3121001208, 26928832879, 28255878334, 30000000001
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OFFSET
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1,3
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LINKS
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MATHEMATICA
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palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 7; Select[Range[0, 10^5], palQ@ f@ # &] (* Giovanni Resta, Aug 29 2018 *)
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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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STATUS
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approved
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