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A102246
Number of distinct prime factors of prime p concatenated p-1 times.
1
1, 2, 3, 5, 7, 9, 10, 10, 10, 11, 19, 16, 14, 20, 9, 12
OFFSET
1,2
EXAMPLE
If p=2, then the number of distinct prime factors of 2 is 1 since 2 is prime.
If p=3, then the number of distinct prime factors of 33 is 2.
If p=5, then the number of distinct prime factors of 5555 is 3.
If p=7, then the number of distinct prime factors of 777777 is 5.
MATHEMATICA
f[n_] := Length[ FactorInteger[ FromDigits[ Flatten[ Table[ IntegerDigits[ Prime[n]], {Prime[n] - 1}]] ]]]; Table[ f[n], {n, 10}]
dpf[n_]:=Module[{p=Prime[n]}, PrimeNu[FromDigits[Flatten[ IntegerDigits/@ Table[p, {p-1}]]]]]; Array[dpf, 16] (* Harvey P. Dale, Aug 20 2013 *)
CROSSREFS
Sequence in context: A118784 A193889 A177922 * A089743 A080587 A342190
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Feb 18 2005
EXTENSIONS
More terms from Robert G. Wilson v, Feb 21 2005
Corrected and extended by Harvey P. Dale, Aug 20 2013
STATUS
approved