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A090959 Index of primorial(n) in A090958. 1
2, 4, 12, 41, 173, 679, 2806, 11221, 46200, 195762, 797388, 3338052, 13821332, 56256665, 230808795 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Significance: a(n+1)-1 is the count of numbers < primorial(n+1) whose largest prime divisor is <= 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 someone derive a general formula (asymptotic)?

LINKS

Table of n, a(n) for n=1..15.

CROSSREFS

Cf. A090958.

Sequence in context: A218144 A222919 A264760 * A244035 A340025 A126942

Adjacent sequences:  A090956 A090957 A090958 * A090960 A090961 A090962

KEYWORD

more,nonn

AUTHOR

Amarnath Murthy, Dec 31 2003

EXTENSIONS

Corrected and extended by David Wasserman, Feb 23 2006

STATUS

approved

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Last modified January 28 00:55 EST 2022. Contains 350654 sequences. (Running on oeis4.)