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 A077807 Number of distinct prime factors of numbers containing in their decimal representation only the digits 0 and 1. 2
 0, 2, 1, 2, 1, 3, 2, 2, 3, 3, 2, 3, 2, 4, 2, 2, 2, 5, 3, 3, 4, 4, 1, 3, 3, 4, 3, 4, 2, 4, 2, 2, 2, 4, 4, 5, 3, 5, 3, 3, 3, 6, 2, 4, 4, 3, 1, 3, 3, 5, 3, 4, 2, 5, 2, 4, 2, 4, 2, 4, 2, 4, 5, 2, 2, 4, 2, 4, 2, 6, 2, 5, 2, 5, 4, 5, 2, 5, 2, 3, 2, 5, 2, 6, 3, 4, 2, 4, 1, 6, 3, 3, 4, 3, 4, 3, 3, 5, 2, 5, 1, 5, 2, 4, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS G. C. Greubel, Table of n, a(n) for n = 1..5000 FORMULA a(n) = A001221(A007088(n)). EXAMPLE a(36) = A001221(A007088(36)) = A001221(100100) = A001221(2*2*5*5*7*11*13) = 5. MATHEMATICA Table[PrimeNu[FromDigits[IntegerDigits[n, 2]]], {n, 1, 50}] (* G. C. Greubel, May 14 2017 *) PROG (PARI) for(n=1, 50, print1(omega(fromdigits(binary(n), 10)), ", ")) \\ G. C. Greubel, May 14 2017 CROSSREFS Cf. A077808. Sequence in context: A076649 A157235 A086289 * A280152 A281574 A191784 Adjacent sequences: A077804 A077805 A077806 * A077808 A077809 A077810 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Nov 16 2002 STATUS approved

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Last modified June 12 13:39 EDT 2024. Contains 373331 sequences. (Running on oeis4.)