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A027728
Palindromes of form k^2 + k + 5.
4
5, 7, 11, 77, 161, 707, 5555, 16261, 50405, 53135, 7570757, 11988911, 16100161, 16544561, 162626261, 502858205, 758919857, 793464397, 11092829011, 11539593511, 5560873780655, 7424090904247, 7702753572077, 16515222251561, 57293477439275, 7246424554246427
OFFSET
1,1
MATHEMATICA
palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 5; Select[f@ Range[0, 10^5], palQ] (* Giovanni Resta, Aug 29 2018 *)
KEYWORD
nonn,base
EXTENSIONS
More terms from Giovanni Resta, Aug 28 2018
STATUS
approved