A159401 Number of n X n arrays of squares of integers summing to 18.

30, 4656, 1785640, 620034300, 186034854330, 41535948202896, 6215087324054848, 583572966788128320, 34534249243423434450, 1358435234100803814340, 37831746939409059248040, 788796221709817955804040, 12886433906907110589156390, 171056501049470927711917200

Offset: 2

Author

R. H. Hardin, Apr 11 2009

Keywords

• nonn

Comments

All such sequences have holonomic recurrences (cf. comment in A159359). - Georg Fischer, Feb 17 2022

Links

• R. H. Hardin, Table of n, a(n) for n = 2..100
• Vaclav Kotesovec, G.f. for A159401
• Index entries for linear recurrences with constant coefficients, signature (37, -666, 7770, -66045, 435897, -2324784, 10295472, -38608020, 124403620, -348330136, 854992152, -1852482996, 3562467300, -6107086800, 9364199760, -12875774670, 15905368710, -17672631900, 17672631900, -15905368710, 12875774670, -9364199760, 6107086800, -3562467300, 1852482996, -854992152, 348330136, -124403620, 38608020, -10295472, 2324784, -435897, 66045, -7770, 666, -37, 1).

Formula

G.f.: see link above. - Vaclav Kotesovec, Dec 04 2012