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A095139 Number of distinct prime factors of A095137(n). 0
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 (list; graph; refs; listen; history; text; internal format)
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: A212300 A165074 A273165 * A109038 A208246 A320857

Adjacent sequences:  A095136 A095137 A095138 * A095140 A095141 A095142

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, May 28 2004

STATUS

approved

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Last modified November 16 22:05 EST 2019. Contains 329208 sequences. (Running on oeis4.)