A159407 Number of n X n arrays of squares of integers summing to 21.

28, 7182, 3923136, 2168352600, 1094602264164, 437181997913808, 123598365410489088, 22732655012770729752, 2620728473996336526900, 193309311936589609598244, 9610726322148658419480768, 340892034159072851206852178, 9072999131907316862007475724

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 A159407
• Index entries for linear recurrences with constant coefficients, signature (43, -903, 12341, -123410, 962598, -6096454, 32224114, -145008513, 563921995, -1917334783, 5752004349, -15338678264, 36576848168, -78378960360, 151532656696, -265182149218, 421171648758, -608359048206, 800472431850, -960566918220, 1052049481860, -1052049481860, 960566918220, -800472431850, 608359048206, -421171648758, 265182149218, -151532656696, 78378960360, -36576848168, 15338678264, -5752004349, 1917334783, -563921995, 145008513, -32224114, 6096454, -962598, 123410, -12341, 903, -43, 1).

Formula

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