OFFSET
1,2
COMMENTS
10^(2*m) - 1 for m > 0 are terms. - Chai Wah Wu, May 25 2017
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..53
P. De Geest, Palindromic quasipronic numbers of the form n(n+2)
FORMULA
a(n) = A028503(n) * (A028503(n) + 2) = A070253(n)^2 - 1 = A070254(n) - 1. - Giovanni Resta, Aug 29 2018
EXAMPLE
4224 belongs to this sequence as 4225 = 65^2.
MATHEMATICA
palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; Select[Range[10000]^2 - 1, palQ] (* Giovanni Resta, Aug 29 2018 *)
Select[Table[n(n+2), {n, 0, 19*10^5}], PalindromeQ] (* Harvey P. Dale, Oct 13 2024 *)
PROG
(ARIBAS): stop := 400000; m := 1; while m < stop do s := m*m - 1; if s = int_reverse(s) then write(s, " "); end; inc(m); end;
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
More terms from Giovanni Resta, Aug 28 2018
STATUS
approved