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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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..16. Dario Alejandro Alpern, Factorization using the Elliptic Curve Method. 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 Cf. A101081, A102245. Sequence in context: A118784 A193889 A177922 * A089743 A080587 A342190 Adjacent sequences: A102243 A102244 A102245 * A102247 A102248 A102249 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

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Last modified September 22 17:32 EDT 2023. Contains 365531 sequences. (Running on oeis4.)