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 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

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