A095139 Number of distinct prime factors of A095137(n).

1, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 1, 2, 2, 2, 2, 1, 2, 3, 1, 2, 2, 3, 1, 2, 3, 2, 2, 1, 2, 2, 2, 6, 2, 1, 3, 4, 5, 2, 5, 3, 2, 3, 3, 3, 3, 2, 4, 3, 4, 5, 6, 1, 3, 2, 4, 2, 2, 4, 3, 2, 3, 6, 4, 6, 4, 3

Offset

1,8

Links

Table of n, a(n) for n=1..72.

Mathematica

PrimeFactors[n_] := Flatten[ Table[ #[[1]], {1} ] & /@ FactorInteger[n]]; f[n_] := Abs[ Product[ Prime[i], {i, 2, n, 2}] + Product[ Prime[i], {i, 1, n, 2}]]; f[1] = 2; Table[ Length[ PrimeFactors[ f[n]]], {n, 72}]

Crossrefs

Cf. A095137.

Sequence in context: A374152 A273165 A336313 * A109038 A208246 A320857

Adjacent sequences: A095136 A095137 A095138 * A095140 A095141 A095142

Keyword

nonn

Author

Robert G. Wilson v, May 28 2004

Status

approved