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a(n) = binomial(n, smallest non-divisor of n).
2

%I #12 May 23 2019 15:54:37

%S 0,0,3,4,10,15,21,56,36,120,55,792,78,364,105,560,136,3060,171,1140,

%T 210,1540,253,42504,300,2600,351,3276,406,27405,465,4960,528,5984,595,

%U 376992,666,8436,741,9880,820,111930,903,13244,990,15180,1081,1712304,1176

%N a(n) = binomial(n, smallest non-divisor of n).

%H Reinhard Zumkeller, <a href="/A242342/b242342.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A007318(n, A007978(n)) for n > 2.

%F a(2*n-1) = A014105(n).

%t Join[{0,0},Table[Binomial[n,Complement[Range[DivisorSigma[0,n]], Divisors[ n]][[1]]],{n,3,50}]] (* _Harvey P. Dale_, May 23 2019 *)

%o (Haskell)

%o a242342 n = if n <= 2 then 0 else a007318' n (a007978 n)

%Y Cf. A014105.

%K nonn

%O 1,3

%A _Reinhard Zumkeller_, May 11 2014