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Search: id:A116504
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| A116504 |
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Number of distinct prime divisors of the concatenation of n,...,1. |
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+0
18
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| 0, 2, 2, 2, 3, 2, 2, 3, 3, 3, 2, 3, 3, 4, 5, 4, 6, 8, 4, 5, 4, 5, 4, 5, 6, 7, 5, 5, 7, 8, 3, 6, 5, 7, 8, 6, 4, 3, 6, 5, 8, 6, 3, 7, 6, 5, 7, 7, 3, 6, 3, 7, 9, 9, 3, 4, 4, 6, 3, 3, 5, 8, 5, 6, 7, 7, 4, 8, 8, 4, 8, 4, 7, 8, 10, 3, 7, 6, 4, 7, 7, 1, 3, 8, 3, 8, 5, 4, 5, 6, 11, 9, 6
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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87654321 = 3*3*1997*4877, distinct prime divisors are 3, 1997 and 4877, hence a(8) = 3.
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MATHEMATICA
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b = {}; a = {}; Do[w = RealDigits[n]; w = First[w]; Do[PrependTo[a, w[[Length[w] - k + 1]]], {k, 1, Length[w]}]; p = FromDigits[a]; m = FactorInteger[p]; AppendTo[b, Length[m]], {n, 1, 30}]; b - Artur Jasinski (grafix(AT)csl.pl), Mar 30 2008
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PROGRAM
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(PARI) {a=""; for(n=1, 58, a=concat(n, a); print1(omega(eval(a)), ", "))}
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CROSSREFS
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Cf. A116505.
Cf. A000422, A116504, A007908, A116505, A104759, A138789, A138790, A138793.
Sequence in context: A053760 A129654 A138789 this_sequence A104011 A099774 A142240
Adjacent sequences: A116501 A116502 A116503 this_sequence A116505 A116506 A116507
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KEYWORD
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nonn,base,more,new
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AUTHOR
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Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Mar 20 2006
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EXTENSIONS
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Edited and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Mar 29 2006
Terms a(59)-a(93) from Sean A. Irvine (sairvin(AT)xtra.co.nz), Nov 04 2009
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