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%I #13 Dec 05 2013 19:56:17
%S 1,2,1,3,1,6,1,4,1,4,1,11,1,4,1,5,1,10,1,9,1,3,1,19,1,4,1,7,1,26,1,5,
%T 1,2,1,25,1,2,1,14,1,25,1,6,1,3,1,30,1,6,1,6,1,16,1,12,1,3,1,81,1,2,1,
%U 6,1,18,1,5,1,18,1,41,1,4,1,3,1,22,1,20,1
%N a(n) = number of primes that can be formed by adding 1 to the product of any subset of the divisors of n.
%C a(2n-1) = 1.
%H Alois P. Heinz, <a href="/A084419/b084419.txt">Table of n, a(n) for n = 1..1000</a>
%e a(6) = 6: the divisors of 6 are 1, 2, 3 and 6 and the divisor products are 1, 2, 3, 6, 12, 18 and 36; the primes arising are 2, 3, 7, 13, 19 and 37.
%e a(12) = 11 = #{2, 3, 5, 7, 13, 19, 37, 73, 97, 433, 577}.
%t Table[Count[Union[Times@@@Subsets[Divisors[n],DivisorSigma[0,n]]]+1,_?PrimeQ],{n,100}] (* _Harvey P. Dale_, Jun 24 2013 *)
%Y Cf. A119607.
%K nonn
%O 1,2
%A _Amarnath Murthy_, Jun 01 2003
%E More terms from _David Wasserman_, Dec 28 2004
%E Corrected by _Harvey P. Dale_, Jun 24 2013