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A023568 Number of distinct prime divisors of prime(n)-3. 3
0, 0, 1, 1, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 1, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 3, 2, 3, 2, 2, 3, 3, 2, 2, 2, 3, 3, 2, 3, 3, 2, 2, 2, 2, 2, 3, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

a(n) = 1 if prime(n) is in A057733. - Robert Israel, Dec 28 2015

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

0, 0, seq(nops(numtheory:-factorset(ithprime(i)-3)), i=3..100); # Robert Israel, Dec 28 2015

MATHEMATICA

Join[{0, 0}, PrimeNu/@(Prime[Range[3, 100]]-3)] (* Harvey P. Dale, Sep 09 2017 *)

CROSSREFS

Cf. A023569, A057733.

Sequence in context: A332992 A337788 A346510 * A081753 A332999 A334144

Adjacent sequences:  A023565 A023566 A023567 * A023569 A023570 A023571

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified May 22 22:13 EDT 2022. Contains 353959 sequences. (Running on oeis4.)