A027717 Palindromes of form k^2 + k + 4.

4, 6, 424, 40204, 48184, 68386, 4002004, 4992994, 6510156, 6830386, 400020004, 424545424, 40000200004, 41162526114, 42314341324, 47678687674, 4000002000004, 4644626264464, 6201427241026, 6866949496686, 400000020000004, 669896222698966, 40000000200000004

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Links

• Giovanni Resta, Table of n, a(n) for n = 1..36
• P. De Geest, Palindromic Quasi_Over_Squares of the form n^2+(n+X)

Crossrefs

Cf. A027716, A027689, A027715, A027728.

Programs

Mathematica

Select[Table[n^2+n+4,{n,0,25*10^5}],IntegerDigits[#] == Reverse[ IntegerDigits[ #]]&] (* Harvey P. Dale, Mar 05 2015 *)
Select[Table[n^2+n+4,{n,0,25*10^5}],PalindromeQ] (* Harvey P. Dale, Dec 23 2023 *)

Extensions

More terms from Giovanni Resta, Aug 29 2018