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A077622

Number of numbers <= prime(n)# having n prime factors (with multiplicity), where prime(n)# = A002110(n) is the n-th primorial.

1, 2, 7, 27, 190, 1621, 17271, 200536, 2757881, 47108763, 843069901, 17797435824

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..12.

FORMULA

a(n) = A077618(A002110(n)), see A077621.

EXAMPLE

a(3)=7, as there are 7 numbers <= prime(3)# = 2*3*5 = 30 having 3 prime factors: 8=2*2*2, 12=2*2*3, 18=2*3*3, 20=2*2*5, 27=3*3*3, 28=2*2*7 and 30=2*3*5.

CROSSREFS

Cf. A001222, A158341.

Sequence in context: A367594 A293031 A255487 * A137108 A294128 A099815

Adjacent sequences: A077619 A077620 A077621 * A077623 A077624 A077625

KEYWORD

nonn,more

AUTHOR

Reinhard Zumkeller, Nov 12 2002

EXTENSIONS

17271 from Sascha Kurz, Jan 04 2003

a(8)-a(11) from Donovan Johnson, Nov 15 2009

a(12) from Donovan Johnson, Jul 16 2011

STATUS

approved

URL: https://oeis.org/A077622

⇱ A077622 - OEIS