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A104524
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Number of distinct prime divisors of 55...557 (with n 5s).
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3
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2, 1, 1, 2, 1, 3, 3, 3, 1, 3, 2, 5, 3, 1, 4, 3, 3, 3, 4, 2, 1, 2, 7, 4, 4, 4, 4, 5, 4, 4, 3, 2, 3, 5, 3, 4, 3, 7, 2, 4, 2, 4, 4, 8, 2, 4, 3, 6, 3, 2
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OFFSET
| 1,1
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FORMULA
| a(n) = A001221(A178769(n+1)). - R. J. Mathar, Aug 24 2011
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EXAMPLE
| The number of distinct prime divisors of 57 is 2.
The number of distinct prime divisors of 557 is 1 (prime).
The number of distinct prime divisors of 5557 is 1 (prime).
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MAPLE
| A104524 := proc(n) local x ; x := [7, seq(5, k=1..n)] ; add(op(i, x)*10^(i-1), i=1..nops(x)) ; numtheory[factorset](%) ; nops(%) ; end proc: # R. J. Mathar, Aug 24 2011
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CROSSREFS
| Cf. A104484, A104483, A104518.
Sequence in context: A025838 A105248 A076302 * A128807 A071628 A033809
Adjacent sequences: A104521 A104522 A104523 * A104525 A104526 A104527
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KEYWORD
| nonn
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AUTHOR
| Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Apr 20 2005
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