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A104658
Number of distinct prime factors of 23 concatenated n times.
1
1, 2, 5, 4, 4, 7, 4, 6, 8, 7, 6, 10, 6, 8, 13, 11, 6, 11, 3, 11, 14, 10, 6, 13, 10, 9, 12, 12, 8, 20, 5, 15, 14, 10, 12, 17, 7, 6, 15, 15, 7, 21, 8, 14, 21, 10, 6, 22, 8, 17, 16, 13, 6, 18, 17, 17, 12, 13, 6, 26, 10, 8, 24, 18, 13, 22, 5, 14, 16, 23, 5, 22, 7
OFFSET
1,2
LINKS
FORMULA
a(n) = A001221((23*100^n-23)/99). - R. J. Mathar, Aug 24 2011
EXAMPLE
Number of distinct prime factors of 23 is 1 (prime).
Number of distinct prime factors of 2323 is 2.
Number of distinct prime factors of 232323 is 5.
MAPLE
A104658 := proc(n) local x ; x := 23 ; for j from 2 to n do x := 100*x+23 ; end do; numtheory[factorset](%) ; nops(%) ; end proc: # R. J. Mathar, Aug 24 2011
MATHEMATICA
Table[PrimeNu[FromDigits[PadRight[{}, 2n, {2, 3}]]], {n, 40}] (* or *) PrimeNu[NestList[100#+23&, 23, 40]] (* Harvey P. Dale, May 21 2012 *)
CROSSREFS
Cf. A001221.
Sequence in context: A021397 A325941 A374391 * A335566 A231730 A095758
KEYWORD
nonn
AUTHOR
Parthasarathy Nambi, Apr 21 2005
EXTENSIONS
More terms from Amiram Eldar, Oct 03 2024
STATUS
approved