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Search: id:A037088
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| A037088 |
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Triangle read by rows: T(n,k) is number of numbers x, 2^n <= x < 2^(n+1), with k prime factors (counted with multiplicity). |
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+0
3
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| 2, 2, 2, 2, 4, 2, 5, 4, 5, 2, 7, 12, 6, 5, 2, 13, 20, 17, 7, 5, 2, 23, 40, 30, 20, 8, 5, 2, 43, 75, 65, 37, 21, 8, 5, 2, 75, 147, 131, 81, 41, 22, 8, 5, 2, 137, 285, 257, 173, 91, 44, 22, 8, 5, 2, 255, 535, 536, 344, 199, 96, 46, 22, 8, 5, 2, 464, 1062, 1033, 736, 403, 215, 99, 47
(list; table; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sequence A092097 gives the limiting behavior at the end of the rows. - T. D. Noe, Feb 22 2008
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LINKS
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T. D. Noe, Rows n=1..24 of triangle, flattened
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EXAMPLE
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The triangular array begins 2; 2,2; 2,4,2; 5,4,5,2; 7,12,6,5,2; ...
a(7) = 5 because the 3-almost primes between 16 and 32 are (18,20,27,28,30).
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CROSSREFS
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A001222 counts factors of n. A000040, A001358, A014612-A014614 are special cases. A036378 and A025488 are applications of binary order A029837. Leading diagonal is essentially A036378 and has partial sums A007053.
Sequence in context: A089818 A067025 A049047 this_sequence A153436 A064486 A153437
Adjacent sequences: A037085 A037086 A037087 this_sequence A037089 A037090 A037091
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KEYWORD
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nonn,tabl,nice
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AUTHOR
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Alford Arnold (Alford1940(AT)aol.com)
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EXTENSIONS
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More terms from Naohiro Nomoto (6284968128(AT)geocities.co.jp), Jun 18 2001
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