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A181807 Number of divisors of A181806(n) that are highly composite (A002182). 4
1, 2, 3, 5, 6, 7, 8, 10, 11, 14, 19, 20, 21, 22, 23, 24, 25, 28, 31, 32, 33, 35, 38, 39, 41, 48, 49, 52, 53, 57, 59, 65, 67, 69, 77, 81, 82, 86, 91, 94, 103, 105, 107, 114, 118, 122, 125, 131, 132, 135, 141, 142, 144, 145, 154, 157, 160, 163, 166, 171, 175, 180 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also, length of row A181806(n) in triangles A181802 and A181803.

LINKS

David A. Corneth, Table of n, a(n) for n = 1..153

A. Flammenkamp, List of the first 1200 highly composite numbers

Eric Weisstein's World of Mathematics, Highly composite number

FORMULA

a(n) = A181801(A181806(n)).

EXAMPLE

A181806(4) = 12 has exactly five divisors (namely, 1, 2, 4, 6 and 12) that are members of A002182.  Hence, a(4) = 5.

CROSSREFS

Cf. A002182, A181801, A181802, A181803, A181806.

Sequence in context: A137620 A336487 A028765 * A059870 A179813 A191914

Adjacent sequences:  A181804 A181805 A181806 * A181808 A181809 A181810

KEYWORD

nonn

AUTHOR

Matthew Vandermast, Nov 27 2010

EXTENSIONS

More terms from Amiram Eldar, Aug 29 2019 (calculated from the b-file at A181806)

STATUS

approved

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Last modified September 23 04:54 EDT 2020. Contains 337295 sequences. (Running on oeis4.)