|
|
A027727
|
|
Palindromes of form k^2 + k + 9.
|
|
3
|
|
|
9, 11, 99, 141, 191, 515, 939, 1001, 19191, 90309, 92729, 93339, 109901, 192291, 939939, 1303031, 1997991, 5605065, 9003009, 9887889, 15066051, 97111179, 900030009, 936696639, 5193003915, 11406560411, 13028282031, 15676667651, 16473337461, 90000300009
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Palindromes h such that 4*h - 35 is a square. - Bruno Berselli, Aug 29 2018
|
|
LINKS
|
|
|
MATHEMATICA
|
palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 9; Select[f@ Range[0, 10^5], palQ] (* Giovanni Resta, Aug 29 2018 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|