A119606 Duplicate of A084419.

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, 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, 6, 1, 18, 1, 5, 1, 18, 1, 41, 1, 4, 1, 3, 1, 22, 1, 20, 1, 3, 1, 71, 1, 3, 1, 11, 1, 76, 1, 5, 1, 3, 1, 38

Offset

1,2

Links

Table of n, a(n) for n=1..96.

Example

The divisors of 4 are D = {1, 2, 4} and the subsets of D are {{}, {1}, {2}, {4}, {1, 2}, {1, 4}, {2, 4}, {1, 2, 4}}. Taking the product of elements in these subsets and adding 1 yields {1, 2, 3, 5, 3, 5, 9, 9}, of which the primes are {2, 3, 5}.

Mathematica

Do[l = Subsets[Divisors[n]]; l = Union[Map[Times @@ # + 1&, l]]; Print[Length[Select[l, PrimeQ]]], {n, 100}]

Crossrefs

Sequence in context: A321738 A022458 A084419 * A034850 A220377 A329696

Adjacent sequences: A119603 A119604 A119605 * A119607 A119608 A119609

Keyword

dead

Author

Ryan Propper, Jun 04 2006

Status

approved