A179535 a(n) = Sum_{k=0..n} binomial(n,k)^2 * binomial(n-k,k)^2 * 81^k.
1, 1, 325, 2917, 247861, 5937301, 265793401, 10705726585, 378746444917, 18588932910901, 657940881863305, 32580334626782185, 1257522211980656425, 59212895251349313865, 2490039488311462939645, 112553667120196462181437
Offset: 0
Keywords
Examples
For n=2 we have a(2) = 1 + 2^2*81 = 325.
Links
- Zhi-Wei Sun, Open Conjectures on Congruences, preprint, arXiv:0911.5665 [math.NT], 2009-2011.
- Zhi-Wei Sun, On Apery numbers and generalized central trinomial coefficients, preprint, arXiv:1006.2776 [math.NT], 2010-2011.
Programs
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Mathematica
a[n_]:=Sum[Binomial[n,k]^2Binomial[n-k,k]^2*81^k,{k,0,n}] Table[a[n],{n,0,25}]
Comments