A159377 Number of n X n arrays of squares of integers with every (n-2) X (n-2) subblock summing to 9.

80, 24734, 15018432, 3417742132, 348819764864, 13957776061203, 290988318683360, 3843118106335319, 36290039874543840, 265026530243707120, 1579438944284211680, 7981229569422064090, 35179752294767789616, 138206917121715744005, 492118001214440275072, 1609539280017323937061

Offset

4,1

Links

R. H. Hardin, Table of n, a(n) for n = 4..22

Robert Israel, Maple code.

Index entries for linear recurrences with constant coefficients, signature (19, -171, 969, -3876, 11628, -27132, 50388, -75582, 92378, -92378, 75582, -50388, 27132, -11628, 3876, -969, 171, -19, 1).

Formula

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

Maple

See uploaded file.

Crossrefs

Sequence in context: A265846 A269145 A187052 * A183582 A068273 A068285

Adjacent sequences: A159374 A159375 A159376 * A159378 A159379 A159380

Keyword

nonn,easy

Author

R. H. Hardin, Apr 11 2009

Status

approved