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a(n) = binomial(sigma(n+1), sigma(n)).
0

%I #6 May 06 2020 21:03:58

%S 3,4,35,0,924,0,6435,0,8568,0,30421755,0,1961256,1,2629575,0,

%T 62359143990,0,513791607420,0,58905,0,36052387482172425,0,4280561376,

%U 0,41648951840265,0,164307576757973059488,0,916312070471295267,0,25827165

%N a(n) = binomial(sigma(n+1), sigma(n)).

%t Table[Binomial[DivisorSigma[1, i + 1], DivisorSigma[1, i]], {i, 1, 50}]

%Y Cf. A000203.

%K nonn

%O 1,1

%A _Joseph L. Pe_, Jan 05 2003