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%I #23 Dec 21 2023 11:02:33
%S 80,24734,15018432,3417742132,348819764864,13957776061203,
%T 290988318683360,3843118106335319,36290039874543840,
%U 265026530243707120,1579438944284211680,7981229569422064090,35179752294767789616,138206917121715744005,492118001214440275072,1609539280017323937061
%N Number of n X n arrays of squares of integers with every (n-2) X (n-2) subblock summing to 9.
%H R. H. Hardin, <a href="/A159377/b159377.txt">Table of n, a(n) for n = 4..22</a>
%H Robert Israel, <a href="/A159377/a159377_1.txt">Maple code</a>.
%H <a href="/index/Rec#order_19">Index entries for linear recurrences with constant coefficients</a>, signature (19, -171, 969, -3876, 11628, -27132, 50388, -75582, 92378, -92378, 75582, -50388, 27132, -11628, 3876, -969, 171, -19, 1).
%F a(n) = (13515097411*n^18 - 732105215136*n^17 + 18022659853008*n^16 - 264583460907504*n^15 + 2541037799402610*n^14 - 16253866320704208*n^13 + 64342727439827164*n^12 - 90791155046116656*n^11 - 622731108657845325*n^10 + 4885459755739725744*n^9 - 17479049408676635172*n^8 + 35521899026299517664*n^7 - 28842561807975597104*n^6 - 51930116239515609600*n^5 + 197442506425287700800*n^4 - 284961424363985723904*n^3 + 214126130786991326208*n^2 - 74249480989045555200*n + 5969870844302131200)/32920473600. - _Robert Israel_, Dec 19 2023
%p See uploaded file.
%K nonn,easy
%O 4,1
%A _R. H. Hardin_, Apr 11 2009
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