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A080947 Numbers having more than three divisors that are also suffixes in binary representation. 3
63, 126, 231, 252, 255, 363, 399, 462, 495, 504, 510, 567, 627, 726, 735, 759, 798, 845, 891, 903, 924, 975, 990, 1008, 1020, 1023, 1071, 1134, 1215, 1239, 1254, 1365, 1407, 1419, 1452, 1455, 1470, 1518, 1575, 1596, 1690, 1695, 1743, 1755, 1782, 1806, 1848 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A080942(a(n))>3.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

EXAMPLE

a(4) = 252: divisors(252) = {1, 2, 3, 4->'100', 6, 7, 9, 12->'1100', 14, 18, 21, 28->'11100', 36, 42, 63, 84, 126, 252->'11111100'}: A080946(252) = #{4, 12, 28, 252} = 4;

a(15) = 735: divisors(735) = {1->'1', 3->'11', 5, 7->'111', 15->'1111', 21, 35, 49, 105, 147, 245, 735->'1011011111'}: A080942(735) = #{1, 3, 7, 15, 735} = 5.

PROG

(Haskell)

a080947 n = a080947_list !! (n-1)

a080947_list = filter ((> 3) . a080942) [1..]

-- Reinhard Zumkeller, Mar 27 2014

CROSSREFS

Cf. A080946, A007088, A080940, A080941.

Sequence in context: A096023 A256813 A324488 * A023720 A031468 A045064

Adjacent sequences:  A080944 A080945 A080946 * A080948 A080949 A080950

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Feb 25 2003

STATUS

approved

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Last modified May 24 11:04 EDT 2022. Contains 354033 sequences. (Running on oeis4.)