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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A257761 Positive integers whose square is the sum of 23 consecutive squares. 12
92, 138, 4278, 6532, 205252, 313398, 9847818, 15036572, 472490012, 721442058, 22669672758, 34614182212, 1087671802372, 1660759304118, 52185576841098, 79681832415452, 2503820016570332, 3823067196637578, 120131175218534838, 183427543606188292 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Positive integers x in the solutions to 2*x^2-46*y^2-1012*y-7590 = 0.

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (0,48,0,-1).

FORMULA

a(n) = 48*a(n-2)-a(n-4).

G.f.: -46*x*(x-1)*(x+2)*(2*x+1) / (x^4-48*x^2+1).

EXAMPLE

92 is in the sequence because 92^2 = 8464 = 7^2+8^2+...+29^2.

MATHEMATICA

LinearRecurrence[{0, 48, 0, -1}, {92, 138, 4278, 6532}, 30] (* Vincenzo Librandi, May 11 2015 *)

PROG

(PARI) Vec(-46*x*(x-1)*(x+2)*(2*x+1)/(x^4-48*x^2+1) + O(x^100))

(Magma) I:=[92, 138, 4278, 6532]; [n le 4 select I[n] else 48*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, May 11 2015

CROSSREFS

Cf. A001032, A001653, A180274, A218395, A257765, A257767, A257780, A257781, A257823-A257828.

Sequence in context: A252068 A046116 A273286 * A252067 A182266 A116215

Adjacent sequences: A257758 A257759 A257760 * A257762 A257763 A257764

KEYWORD

nonn,easy

AUTHOR

Colin Barker, May 07 2015

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 December 6 14:43 EST 2022. Contains 358644 sequences. (Running on oeis4.)