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!)
A216446 Palindromic numbers which can be written as the sum of two or more consecutive squares. 3
5, 55, 77, 181, 313, 434, 505, 545, 595, 636, 818, 1001, 1111, 1441, 1771, 4334, 6446, 17371, 17871, 19691, 21712, 41214, 42924, 44444, 46564, 51015, 65756, 81818, 97679, 99199, 108801, 127721, 137731, 138831, 139931, 148841, 161161, 166661, 171171, 188881 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
V. Raman and Giovanni Resta, Table of n, a(n) for n = 1..10306 (terms < 10^18, first 298 terms from V. Raman)
EXAMPLE
636 is in the sequence because it is a palindrome and 636 = 4^2+5^2+6^2+7^2+8^2+9^2+10^2+11^2+12^2.
MATHEMATICA
palQ[n_] := Block[{d = IntegerDigits@ n}, d == Reverse@ d]; upto = 10^6; Union[ Reap[ For[i=1, s=i^2 + (i+1)^2; s < upto, i++, For[j=i+1, s < upto, j++; s += j^2, If[palQ[s], Sow@ s]]]][[2, 1]]] (* Giovanni Resta, Jun 14 2018 *)
With[{nn=200}, Select[Union[Flatten[Table[Total/@Partition[Range[nn]^2, n, 1], {n, 2, nn}]]], PalindromeQ]] (* Harvey P. Dale, Oct 17 2021 *)
CROSSREFS
Cf. A034705, A180436, A267600 (terms with more than one representation).
Sequence in context: A247711 A284066 A244439 * A307991 A015221 A035305
KEYWORD
nonn,base
AUTHOR
V. Raman, Sep 07 2012
EXTENSIONS
Errors in previous b-file noticed by Riley Waugh, Jun 13 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 12 23:56 EDT 2024. Contains 373362 sequences. (Running on oeis4.)