The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A027580 Palindromes of the form n^2 + (n+1)^2 + (n+2)^2 + (n+3)^2 + (n+4)^2. 2
55, 51015, 554455, 51488415, 510151015, 55883648705050784638855, 531578379527444725973875135 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Terms start and end with the digit 5 since all terms are divisible by 5, i.e., the corresponding values of n are odd (see A027579). - Chai Wah Wu, Jan 18 2016
LINKS
MATHEMATICA
Select[Table[n^2 + (n + 1)^2 + (n + 2)^2 + (n + 3)^2 + (n + 4)^2, {n, 10^7}], # == Reverse@ # &@ IntegerDigits@ # &] (* Michael De Vlieger, Jan 24 2016 *)
Select[Table[5x^2+20x+30, {x, 11000}], PalindromeQ] (* The program generates the first 5 terms of the sequence. To generate more, increase the x constant but the program may take a long time to run. *) (* Harvey P. Dale, Sep 16 2023 *)
PROG
(Python)
A027580_list = []
for i in range(1, 10**8, 2):
s = str(5*(i*(i+4)+6))
if s == s[::-1]:
A027580_list.append(int(s)) # Chai Wah Wu, Jan 18 2016
CROSSREFS
Cf. A027579.
Sequence in context: A221000 A196428 A231907 * A265980 A287053 A046194
KEYWORD
nonn,base,more
AUTHOR
EXTENSIONS
a(6) from Chai Wah Wu, Jan 18 2016
a(7) from Giovanni Resta, Aug 04 2019
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 14 08:24 EDT 2024. Contains 373393 sequences. (Running on oeis4.)