login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A027720 Palindromes of form k^2 + 1. 5
1, 2, 5, 101, 626, 10001, 1000001, 1040401, 2217122, 5053505, 100000001, 101808101, 10000000001, 10182828101, 10408080401, 28053235082, 1000000000001, 1000400040001, 1018262628101, 7534662664357, 100000000000001, 100018000810001, 101826464628101 (list; graph; refs; listen; history; text; internal format)
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..48

P. De Geest, Palindromic incremented squares of the form n^2+1

FORMULA

a(n) = A027719(n)^2 + 1. - Giovanni Resta, Aug 29 2018

MATHEMATICA

palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; Select[Range[0, 10^5]^2 + 1, palQ] (* Giovanni Resta, Aug 29 2018 *)

CROSSREFS

Cf. A002522, A027719, A070254, A002779.

Sequence in context: A120800 A277341 A066618 * A132482 A208209 A276267

Adjacent sequences:  A027717 A027718 A027719 * A027721 A027722 A027723

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

EXTENSIONS

More terms from Giovanni Resta, Aug 28 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 18 07:55 EST 2022. Contains 350454 sequences. (Running on oeis4.)