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Palindromes of form k^2 + k + 8.
3

%I #15 Aug 11 2024 14:41:29

%S 8,878,41014,81518,8558558,8617168,415242514,874414478,88279997288,

%T 8035521255308,8053537353508,8942435342498,8984014104898,

%U 82375268486257328,8563985811185893658,41023644811311844632014,87279499176567199497278,462070049490878094940070264,467190356216898612653091764

%N Palindromes of form k^2 + k + 8.

%C Palindromes h such that 4*h - 31 is a square. - _Bruno Berselli_, Aug 29 2018

%H P. De Geest, <a href="https://www.worldofnumbers.com/quasimor.htm">Palindromic Quasi_Over_Squares of the form n^2+(n+X)</a>

%t palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 8; Select[f@ Range[0, 3*10^5], palQ] (* _Giovanni Resta_, Aug 29 2018 *)

%Y Cf. A027724, A027693, A027723, A027727.

%K nonn,base

%O 1,1

%A _Patrick De Geest_

%E a(14)-a(19) from _Giovanni Resta_, Aug 29 2018