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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
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
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.)