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Search: id:A090959
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| 2, 4, 12, 41, 173, 679, 2806, 11221, 46200, 195762, 797388, 3338052, 13821332, 56256665, 230808795
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Significance: a(n+1)-1 is the count of numbers < primorial(n+1) which have the largest prime divisor <= prime(n). e.g. a(5) = 39 is the index of 210=2*3*5*7 in A090958. which means there are 38 numbers of the form 2^a*3^b*5^c < 210. Can some one derive a general formula (asymptotic)?
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CROSSREFS
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Cf. A090958.
Sequence in context: A062962 A033472 A134983 this_sequence A126942 A126947 A063179
Adjacent sequences: A090956 A090957 A090958 this_sequence A090960 A090961 A090962
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KEYWORD
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more,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Dec 31 2003
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EXTENSIONS
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Corrected and extended by David Wasserman (wasserma(AT)spawar.navy.mil), Feb 23 2006
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