A257200 a(n) = n*(n+1)*(n+2)*(n+3)*(n^2+3*n+26)/720.
1, 6, 22, 63, 154, 336, 672, 1254, 2211, 3718, 6006, 9373, 14196, 20944, 30192, 42636, 59109, 80598, 108262, 143451, 187726, 242880, 310960, 394290, 495495, 617526, 763686, 937657, 1143528, 1385824, 1669536, 2000152, 2383689, 2826726, 3336438, 3920631, 4587778, 5347056, 6208384, 7182462
Offset: 1
Examples
Array in Comments begins: 1, 5, 15, 35, 70, 126, 210, 330, ... 1, 6, 20, 50, 105, 196, 336, 540, ... 1, 7, 25, 65, 140, 266, 462, 750, ... 1, 8, 30, 80, 175, 336, 588, 960, ... 1, 9, 35, 95, 210, 406, 714, 1170, ... 1, 10, 40, 110, 245, 476, 840, 1380, ...
Links
- D. A. Sardelis and T. M. Valahas, On Multidimensional Pythagorean Numbers, arXiv:0805.4070 [math.GM], 2008.
- Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).
Programs
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Magma
[n*(n+1)*(n+2)*(n+3)*(n^2+3*n+26)/720: n in [1..40]]; // Vincenzo Librandi, Apr 18 2015
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Mathematica
Table[n (n + 1) (n + 2) (n + 3) (n^2 + 3n + 26)/720, {n, 40}]
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PARI
first(m)=vector(m,i,i*(i+1)*(i+2)*(i+3)*(i^2+3*i+26)/720) \\ Anders Hellström, Aug 26 2015
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PARI
Vec(x*(-1 + x - x^2)/(-1 + x)^7 + O(x^40)) \\ Michel Marcus, Aug 27 2015
Formula
G.f.: x*(-1 + x - x^2)/(-1 + x)^7.
Comments